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The 'XML2RFC' version 2 Vocabulary
draft-reschke-xml2rfc-08

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This is an older version of an Internet-Draft whose latest revision state is "Replaced".
Author Julian Reschke
Last updated 2014-06-12
Replaced by draft-iab-xml2rfcv2, RFC 7749
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draft-reschke-xml2rfc-08
Network Working Group                                         J. Reschke
Internet-Draft                                                greenbytes
Obsoletes: 2629 (if approved)                              June 12, 2014
Intended status: Informational
Expires: December 14, 2014

                   The 'XML2RFC' version 2 Vocabulary
                        draft-reschke-xml2rfc-08

Abstract

   This document defines the 'XML2RFC' version 2 vocabulary; an XML-
   based language used for writing RFCs and Internet-Drafts.

Editorial Note (To be removed by RFC Editor)

   Discussion of this draft takes place on the XML2RFC mailing list
   (xml2rfc@ietf.org), which has its home page at
   <https://www.ietf.org/mailman/listinfo/xml2rfc>.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 14, 2014.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect

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   to this document.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Syntax Notation  . . . . . . . . . . . . . . . . . . . . .  4
   2.  Elements . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.1.  <abstract> . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  <address>  . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.3.  <annotation> . . . . . . . . . . . . . . . . . . . . . . .  5
     2.4.  <area> . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     2.5.  <artwork>  . . . . . . . . . . . . . . . . . . . . . . . .  6
     2.6.  <author> . . . . . . . . . . . . . . . . . . . . . . . . .  8
     2.7.  <back> . . . . . . . . . . . . . . . . . . . . . . . . . .  9
     2.8.  <c>  . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     2.9.  <city> . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     2.10. <code> . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     2.11. <country>  . . . . . . . . . . . . . . . . . . . . . . . . 11
     2.12. <cref> . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     2.13. <date> . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     2.14. <email>  . . . . . . . . . . . . . . . . . . . . . . . . . 12
     2.15. <eref> . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     2.16. <facsimile>  . . . . . . . . . . . . . . . . . . . . . . . 13
     2.17. <figure> . . . . . . . . . . . . . . . . . . . . . . . . . 13
     2.18. <format> . . . . . . . . . . . . . . . . . . . . . . . . . 15
     2.19. <front>  . . . . . . . . . . . . . . . . . . . . . . . . . 15
     2.20. <iref> . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     2.21. <keyword>  . . . . . . . . . . . . . . . . . . . . . . . . 17
     2.22. <list> . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     2.23. <middle> . . . . . . . . . . . . . . . . . . . . . . . . . 19
     2.24. <note> . . . . . . . . . . . . . . . . . . . . . . . . . . 19
     2.25. <organization> . . . . . . . . . . . . . . . . . . . . . . 20
     2.26. <phone>  . . . . . . . . . . . . . . . . . . . . . . . . . 20
     2.27. <postal> . . . . . . . . . . . . . . . . . . . . . . . . . 20
     2.28. <postamble>  . . . . . . . . . . . . . . . . . . . . . . . 21
     2.29. <preamble> . . . . . . . . . . . . . . . . . . . . . . . . 21
     2.30. <reference>  . . . . . . . . . . . . . . . . . . . . . . . 22
     2.31. <references> . . . . . . . . . . . . . . . . . . . . . . . 22
     2.32. <region> . . . . . . . . . . . . . . . . . . . . . . . . . 23
     2.33. <rfc>  . . . . . . . . . . . . . . . . . . . . . . . . . . 23
     2.34. <section>  . . . . . . . . . . . . . . . . . . . . . . . . 27
     2.35. <seriesInfo> . . . . . . . . . . . . . . . . . . . . . . . 28
     2.36. <spanx>  . . . . . . . . . . . . . . . . . . . . . . . . . 28
     2.37. <street> . . . . . . . . . . . . . . . . . . . . . . . . . 29
     2.38. <t>  . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
     2.39. <texttable>  . . . . . . . . . . . . . . . . . . . . . . . 30
     2.40. <title>  . . . . . . . . . . . . . . . . . . . . . . . . . 32
     2.41. <ttcol>  . . . . . . . . . . . . . . . . . . . . . . . . . 32

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     2.42. <uri>  . . . . . . . . . . . . . . . . . . . . . . . . . . 33
     2.43. <vspace> . . . . . . . . . . . . . . . . . . . . . . . . . 33
     2.44. <workgroup>  . . . . . . . . . . . . . . . . . . . . . . . 34
     2.45. <xref> . . . . . . . . . . . . . . . . . . . . . . . . . . 34
   3.  Escaping for use in XML  . . . . . . . . . . . . . . . . . . . 36
   4.  Special Unicode Code Points  . . . . . . . . . . . . . . . . . 36
   5.  Including Files  . . . . . . . . . . . . . . . . . . . . . . . 37
   6.  Internationalization Considerations  . . . . . . . . . . . . . 38
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 38
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 38
     8.1.  Internet Media Type Registration . . . . . . . . . . . . . 38
   9.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 39
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 40
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 40
     10.2. Informative References . . . . . . . . . . . . . . . . . . 40
   Appendix A.  Front Page Generation . . . . . . . . . . . . . . . . 42
     A.1.  The /rfc/@category Attribute . . . . . . . . . . . . . . . 42
     A.2.  The /rfc/@ipr Attribute  . . . . . . . . . . . . . . . . . 42
       A.2.1.  Current Values: '*trust200902' . . . . . . . . . . . . 43
       A.2.2.  Historic Values  . . . . . . . . . . . . . . . . . . . 45
   Appendix B.  Changes from RFC 2629 ('v1')  . . . . . . . . . . . . 45
     B.1.  Removed Elements . . . . . . . . . . . . . . . . . . . . . 45
     B.2.  Changed Defaults . . . . . . . . . . . . . . . . . . . . . 45
     B.3.  Changed Elements . . . . . . . . . . . . . . . . . . . . . 46
     B.4.  New Elements . . . . . . . . . . . . . . . . . . . . . . . 46
   Appendix C.  Relax NG Schema . . . . . . . . . . . . . . . . . . . 46
     C.1.  Checking Validity  . . . . . . . . . . . . . . . . . . . . 52
   Appendix D.  Proposed Future Changes for 'v3'  . . . . . . . . . . 52
     D.1.  Contact Information  . . . . . . . . . . . . . . . . . . . 53
     D.2.  Figures  . . . . . . . . . . . . . . . . . . . . . . . . . 53
     D.3.  Linking  . . . . . . . . . . . . . . . . . . . . . . . . . 53
     D.4.  Lists  . . . . . . . . . . . . . . . . . . . . . . . . . . 54
     D.5.  References . . . . . . . . . . . . . . . . . . . . . . . . 54
     D.6.  Archival Considerations  . . . . . . . . . . . . . . . . . 54
     D.7.  Document Metadata  . . . . . . . . . . . . . . . . . . . . 54
     D.8.  Including Material . . . . . . . . . . . . . . . . . . . . 55
     D.9.  Misc.  . . . . . . . . . . . . . . . . . . . . . . . . . . 55
   Index  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

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1.  Introduction

   This document describes version 2 ('v2') of the 'XML2RFC' vocabulary;
   an XML-based language ('Extensible Markup Language', [XML]) used for
   writing RFCs ([RFCSTYLE]) and Internet-Drafts ([IDGUIDE]).

   It obsoletes the original version ("v1") [RFC2629], which contained
   the original language definition, and which was subsequently extended
   ("v2").  Furthermore, it discusses potential extensions in a future
   revision ("v3").

   Note that the vocabulary contains certain constructs that might not
   be used when generating the final text; however, they can provide
   useful data for other uses (such index generation, populating a
   keyword database, or syntax checks).

1.1.  Syntax Notation

   The XML vocabulary here is defined in prose, based on the Relax NG
   schema ([RNC]) contained in Appendix C (specified in Relax NG Compact
   Notation, "RNC").

   Note that the schema can be used for automated validity checks, but
   certain constraints are only described in prose (example: the
   conditionally required presence of the "abbrev" attribute).

2.  Elements

   The sections below describe all elements and their attributes.

   Note that attributes not labeled "mandatory" are optional.

2.1.  <abstract>

   Contains the abstract of the document.  The abstract ought to be
   self-contained and thus should not contain references or unexpanded
   abbreviations.  See Section 4.3 of [RFCSTYLE] for more information.

   This element appears as child element of: <front> (Section 2.19).

   Content model:

   One or more <t> elements (Section 2.38)

2.2.  <address>

   Provides address information for the author.

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   This element appears as child element of: <author> (Section 2.6).

   Content model:

   In this order:

   1.  One optional <postal> element (Section 2.27)

   2.  One optional <phone> element (Section 2.26)

   3.  One optional <facsimile> element (Section 2.16)

   4.  One optional <email> element (Section 2.14)

   5.  One optional <uri> element (Section 2.42)

2.3.  <annotation>

   Provides additional prose augmenting a bibliographical reference.

   For instance:

   <annotation>
     Latest version available at <eref
     target='http://www.w3.org/TR/xml'/>.
   </annotation>

   ...will generate the text used in the reference for [XML].

   This element appears as child element of: <reference> (Section 2.30).

   Content model:

   In any order:

   o  Text

   o  <xref> elements (Section 2.45)

   o  <eref> elements (Section 2.15)

   o  <iref> elements (Section 2.20)

   o  <cref> elements (Section 2.12)

   o  <spanx> elements (Section 2.36)

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2.4.  <area>

   Provides information about the IETF area to which this document
   relates (currently not used when generating documents).

   The value ought to be either the fullname or the abbreviation of one
   of the IETF areas as listed on <http://www.ietf.org/iesg/area.html>.
   The list at the time that this document is being published is:
   "Applications", "app", "General", "gen", "Internet", "int",
   "Operations and Management", "ops", "Real-time Applications and
   Infrastructure", "rai", "Routing", "rtg", "Security", "sec",
   "Transport", "tsv".

   This element appears as child element of: <front> (Section 2.19).

   Content model: only text content.

2.5.  <artwork>

   This element allows the inclusion of "artwork" into the document.

   <artwork> is the only element in the vocabulary that provides full
   control of horizontal whitespace and line breaks, and thus is used
   for a variety of things, such as:

   o  diagrams ("line art"),

   o  source code,

   o  formal languages (such as ABNF or the RNC notation used in this
      document),

   o  complex tables, or

   o  protocol unit diagrams.

   Alternatively, the "src" attribute allows referencing an external
   graphics file, such as a bitmap or a vector drawing, using a URI.  In
   this case, the textual content acts as fallback for output formats
   that do not support graphics, and thus ought to contain either a
   "line art" variant of the graphics, or otherwise prose that describes
   the included image in sufficient detail.  Note that RFCs occasionally
   are published with enhanced diagrams; a recent example is [RFC5598].

   This element appears as child element of: <figure> (Section 2.17).

   Content model:

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   Text

2.5.1.  'align' attribute

   Controls whether the artwork appears left (default), centered, or
   right.

   Allowed values:

   o  "left" (default)

   o  "center"

   o  "right"

2.5.2.  'alt' attribute

   Alternative text description of the artwork (not just the caption).

2.5.3.  'height' attribute

   The suggested height of the graphics included using the "src"
   attribute.

   This attribute is format-dependent and ought to be avoided.

   When generating HTML output, current implementations copy the
   attribute "as is".  For other output formats it is usually ignored.

2.5.4.  'name' attribute

   A filename suitable for the contents (such as for extraction to a
   local file).

   This attribute generally isn't used for document generation, but it
   can be helpful for other kinds of tools (such as automated syntax
   checkers which work by extracting the source code).

2.5.5.  'src' attribute

   The URI of a graphics file.

   Note that this can be a "data" URI ([RFC2397]) as well, in which case
   the graphics file is wholly part of the XML file.

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2.5.6.  'type' attribute

   Specifies the type of the artwork.

   The value either is a well-known keyword (such as "abnf"), or an
   Internet Media Type (see [RFC2046]).

   How it is used depends on context and application.  For instance, a
   formatter can attempt to syntax-highlight code in certain known
   languages.

2.5.7.  'width' attribute

   The suggested width of the graphics included using the "src"
   attribute.

   This attribute is format-dependent and ought to be avoided.

   When generating HTML output, current implementations copy the
   attribute "as is".  For other output formats it is usually ignored.

2.5.8.  'xml:space' attribute

   Determines whitespace handling.

   "preserve" is both the default value and the only meaningful setting
   anyway (because that's what the <artwork> element is for).

   See also Section 2.10 of [XML].

   Allowed values:

   o  "default"

   o  "preserve" (default)

2.6.  <author>

   Provides information about a document's author.  This is used both
   for the document itself (at the beginning of the document) and for
   referenced documents (inside of <reference>).

   The <author> elements contained within the document's <front> element
   are used to fill the boilerplate, and also to generate the "Author's
   Address" section (see Section 4.12 of [RFCSTYLE]).

   Note that an "author" can also be just an organization (by not
   specifying any of the name attributes, but adding the <organization>

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   child element).

   Furthermore, the "role" attribute can be used to mark an author as
   "editor".  This is reflected both on the front page and in
   bibliographical references.  Note that this specification does not
   define a precise meaning for the term "editor".

   See Section "Authors vs. Contributors" of [RFCPOLICY] for more
   information.

   This element appears as child element of: <front> (Section 2.19).

   Content model:

   In this order:

   1.  One optional <organization> element (Section 2.25)

   2.  One optional <address> element (Section 2.2)

2.6.1.  'fullname' attribute

   The full name (used in the automatically generated "Author's Address"
   section).

2.6.2.  'initials' attribute

   Author initials (used on the front page and in references).

   Initials should be provided as a whitespace separated list of pairs
   of a letter and a dot.

2.6.3.  'role' attribute

   Specifies the role the author had in creating the document.

   Allowed values:

   o  "editor"

2.6.4.  'surname' attribute

   The author's surname.

2.7.  <back>

   Contains the "back" part of the document: the references and
   appendices.  In <back>, <section> elements indicate appendices.

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   This element appears as child element of: <rfc> (Section 2.33).

   Content model:

   In this order:

   1.  Optional <references> elements (Section 2.31)

   2.  Optional <section> elements (Section 2.34)

2.8.  <c>

   Provides the content of a cell in a table.

   This element appears as child element of: <texttable> (Section 2.39).

   Content model:

   In any order:

   o  Text

   o  <xref> elements (Section 2.45)

   o  <eref> elements (Section 2.15)

   o  <iref> elements (Section 2.20)

   o  <cref> elements (Section 2.12)

   o  <spanx> elements (Section 2.36)

2.9.  <city>

   Gives the city name in a postal address.

   This element appears as child element of: <postal> (Section 2.27).

   Content model: only text content.

2.10.  <code>

   Gives the postal region code.

   This element appears as child element of: <postal> (Section 2.27).

   Content model: only text content.

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2.11.  <country>

   Gives the country in a postal address.

   This element appears as child element of: <postal> (Section 2.27).

   Content model: only text content.

2.12.  <cref>

   Represents a comment.

   Comments can be used in a document while it is work-in-progress.
   They usually appear either inline and visually highlighted, at the
   end of the document (depending on file format and settings of the
   formatter), or not at all (when generating an RFC).

   This element appears as child element of: <annotation> (Section 2.3),
   <c> (Section 2.8), <postamble> (Section 2.28), <preamble>
   (Section 2.29), and <t> (Section 2.38).

   Content model: only text content.

2.12.1.  'anchor' attribute

   Document-wide unique identifier for this comment.  The processor will
   auto-generate an identifier when none is given.

   The value needs to be a valid XML "Name" (Section 2.3 of [XML]),
   additionally constrained to US-ASCII characters ([USASCII]).

2.12.2.  'source' attribute

   Holds the "source" of a comment, such as the name or the initials of
   the person who made the comment.

2.13.  <date>

   Provides information about the publication date.

   Note that this element is used both for the boilerplate of the
   document being produced, and also inside bibliographic references.

   In the first case, it defines the publication date, which, when
   producing Internet-Drafts, will be used for computing the expiration
   date (see Section 8 of [IDGUIDE]).  When "year", "month" or "day" are
   left out, the processor will attempt to use the current system date
   if the attributes that are specified do match the system date.

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   Note that in the first case, month names need to match the full
   (English) month name ("January", "February", "March", "April", "May,
   "June", "July", "August", "September", "October", "November", or
   "December") in order for expiration calculations to work (some
   implementations might support additional formats, though).

   In the second case, the date information can have prose text for the
   month or year.  For example, vague dates (year="ca. 2000"), date
   ranges (year="2012-2013") non-specific months (month="Second
   quarter") and so on, are allowed.

   This element appears as child element of: <front> (Section 2.19).

   Content model: this element does not have any contents.

2.13.1.  'day' attribute

   Day of publication; this is a number.

2.13.2.  'month' attribute

   Month of publication; this is the English name of the month.

2.13.3.  'year' attribute

   Year of publication.

2.14.  <email>

   Provides an email address.

   The value is expected to be the scheme-specific part of a "mailto"
   URI (so does not include the prefix "mailto:").  See Section 2 of
   [RFC6068] for details.

   This element appears as child element of: <address> (Section 2.2).

   Content model: only text content.

2.15.  <eref>

   Represents an "external" link (as specified in the "target"
   attribute).

   If the element has text content, that content will be used.
   Otherwise, the value of the target attribute will be inserted in
   angle brackets ([RFC3986], Appendix C).

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   This element appears as child element of: <annotation> (Section 2.3),
   <c> (Section 2.8), <postamble> (Section 2.28), <preamble>
   (Section 2.29), and <t> (Section 2.38).

   Content model: only text content.

2.15.1.  'target' attribute (mandatory)

   URI of the link target (see Section 3 of [RFC3986]).

2.16.  <facsimile>

   Represents the phone number of a fax machine.

   The value is expected to be the scheme-specific part of a "tel" URI
   (so does not include the prefix "tel:"), using the "global numbers"
   syntax.  See Section 3 of [RFC3966] for details.

   This element appears as child element of: <address> (Section 2.2).

   Content model: only text content.

2.17.  <figure>

   This element is used to represent a figure, consisting of an optional
   preamble, the actual figure, an optional postamble, and an optional
   title.

   This element appears as child element of: <section> (Section 2.34),
   and <t> (Section 2.38).

   Content model:

   In this order:

   1.  Optional <iref> elements (Section 2.20)

   2.  One optional <preamble> element (Section 2.29)

   3.  One <artwork> element (Section 2.5)

   4.  One optional <postamble> element (Section 2.28)

2.17.1.  'align' attribute

   Used to change the alignment of <preamble> and <postamble>.

   Note: does not affect title or <artwork> alignment.

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   Allowed values:

   o  "left" (default)

   o  "center"

   o  "right"

2.17.2.  'alt' attribute

   Duplicates functionality available on <artwork>; avoid it.

2.17.3.  'anchor' attribute

   Document-wide unique identifier for this figure.

   Furthermore, the presence of this attribute causes the figure to be
   numbered.

   The value needs to be a valid XML "Name" (Section 2.3 of [XML]).

2.17.4.  'height' attribute

   Duplicates functionality available on <artwork>; avoid it.

2.17.5.  'src' attribute

   Duplicates functionality available on <artwork>; avoid it.

2.17.6.  'suppress-title' attribute

   Figures that have an "anchor" attribute will automatically get an
   autogenerated title (such as "Figure 1"), even if the "title"
   attribute is absent.  Setting this attribute to "true" will prevent
   this.

   Allowed values:

   o  "true"

   o  "false" (default)

2.17.7.  'title' attribute

   The title for the figure; this usually appears on a line after the
   figure.

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2.17.8.  'width' attribute

   Duplicates functionality available on <artwork>; avoid it.

2.18.  <format>

   Provides a link to an additional format variant for a reference.

   Note that these additional links are neither used in published RFCs,
   nor supported by all tools.  If the goal is to provide a single URI
   for a reference, the "target" attribute on <reference> can be used
   instead.

   This element appears as child element of: <reference> (Section 2.30).

   Content model: this element does not have any contents.

2.18.1.  'octets' attribute

   Octet length of linked-to document.

2.18.2.  'target' attribute

   URI of document.

2.18.3.  'type' attribute (mandatory)

   The type of the linked-to document, such as "TXT", "HTML", or "PDF".

2.19.  <front>

   Represent the "front matter": metadata (such as author information),
   abstract, and additional notes.

   This element appears as child element of: <reference> (Section 2.30),
   and <rfc> (Section 2.33).

   Content model:

   In this order:

   1.  One <title> element (Section 2.40)

   2.  One or more <author> elements (Section 2.6)

   3.  One <date> element (Section 2.13)

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   4.  Optional <area> elements (Section 2.4)

   5.  Optional <workgroup> elements (Section 2.44)

   6.  Optional <keyword> elements (Section 2.21)

   7.  One optional <abstract> element (Section 2.1)

   8.  Optional <note> elements (Section 2.24)

2.20.  <iref>

   Provides terms for the document's index.

   Index entries can be either single items (when just the "item"
   attribute is given) or nested items (by specifying "subitem" as
   well).

   For instance:

   <iref item="Grammar" subitem="item"/>

   will produce an index entry for "Grammar, item".

   This element appears as child element of: <annotation> (Section 2.3),
   <c> (Section 2.8), <figure> (Section 2.17), <postamble>
   (Section 2.28), <preamble> (Section 2.29), <section> (Section 2.34),
   and <t> (Section 2.38).

   Content model: this element does not have any contents.

2.20.1.  'item' attribute (mandatory)

   The item to include.

2.20.2.  'primary' attribute

   Setting this to "true" declares the occurrence as "primary", which
   might cause it to be highlighted in the index.

   Allowed values:

   o  "true"

   o  "false" (default)

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2.20.3.  'subitem' attribute

   The subitem to include.

2.21.  <keyword>

   Specifies a keyword applicable to the document.

   Note that each element should only contain a single keyword; for
   multiple keywords, the element can simply be repeated.

   Keywords are used both in the RFC Index and in the metadata of
   generated document formats.

   This element appears as child element of: <front> (Section 2.19).

   Content model: only text content.

2.22.  <list>

   Delineates a text list.

   Each list item is represented by a <t> element.  The vocabulary
   currently does not directly support list items consisting of multiple
   paragraphs; if this is needed, <vspace> (Section 2.43) can be used as
   workaround.

   This element appears as child element of: <t> (Section 2.38).

   Content model:

   One or more <t> elements (Section 2.38)

2.22.1.  'counter' attribute

   This attribute holds a token that serves as an identifier for a
   counter.  The intended use is continuation of lists.

   Note that this attribute functions only when the style attribute is
   using the "format..." syntax (Section 2.22.3); otherwise, it is
   ignored.

2.22.2.  'hangIndent' attribute

   For list styles with potentially wide labels, this attribute can
   override the default indentation level, measured in characters.

   Note that it only affects style with variable-width labels

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   ("format..." and "hanging", see below), and it may not affect formats
   in which the list item text appears _below_ the label.

2.22.3.  'style' attribute

   This attribute is used to control the display of a list.

   The value of this attribute is inherited by any nested lists that do
   not have this attribute set.  It may be set to:

   "empty" (or not set)

      For unlabeled list items; it can also be used for indentation
      purposes (this is the default value).

   "hanging"

      For lists where the items are labeled with a piece of text.

      The label text is specified in the 'hangText' attribute of the <t>
      element (Section 2.38.2).

   "letters"

      For ordered lists using letters as labels (lowercase letters
      followed by a period; after "z", it rolls over to a two-letter
      format).  For nested lists, processors usually flip between
      uppercase and lowercase.

   "numbers"

      For ordered lists using numbers as labels.

   "symbols"

      For unordered (bulleted) lists.

      The style of the bullets is chosen automatically be the processor
      (some implementations allow overriding the default using a
      processing instruction).

   And, finally:

   "format ..."

      For lists with customized labels, consisting of fixed text and an
      item counter in various formats.

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      The value is a free-form text that allows counter values to be
      inserted using a "percent-letter" format.  For instance, "[REQ%d]"
      generates labels of the form "[REQ1]", where "%d" inserts the item
      number as decimal number.

      The following formats are supported:

      %c lowercase letters (a, b, c, etc.)

      %C uppercase letters (A, B, C, etc.)

      %d decimal numbers (1, 2, 3, etc.)

      %i lowercase Roman numerals (i, ii, iii, etc.)

      %I uppercase Roman numerals (I, II, III, etc.)

      %% represents a percent sign

      Other formats are reserved for future use.

2.23.  <middle>

   Represents the main content of the document.

   This element appears as child element of: <rfc> (Section 2.33).

   Content model:

   One or more <section> elements (Section 2.34)

2.24.  <note>

   Creates an unnumbered section that appears after the abstract.

   It is usually used for additional information to reviewers (working
   group information, mailing list, ...), or for additional publication
   information such as "IESG Notes".

   This element appears as child element of: <front> (Section 2.19).

   Content model:

   One or more <t> elements (Section 2.38)

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2.24.1.  'title' attribute (mandatory)

   The title of the note.

2.25.  <organization>

   Specifies the affiliation of an author.

   This information appears in both the "Author's Address" section and
   on the front page (see [RFCSTYLE], Section 4.1.1 for more
   information).  If the value is long, an abbreviated variant can be
   specified in the "abbrev" attribute.

   This element appears as child element of: <author> (Section 2.6).

   Content model: only text content.

2.25.1.  'abbrev' attribute

   Abbreviated variant.

2.26.  <phone>

   Represents a phone number.

   The value is expected to be the scheme-specific part of a "tel" URI
   (so does not include the prefix "tel:"), using the "global numbers"
   syntax.  See Section 3 of [RFC3966] for details.

   This element appears as child element of: <address> (Section 2.2).

   Content model: only text content.

2.27.  <postal>

   Contains child elements providing postal information.

   This element appears as child element of: <address> (Section 2.2).

   Content model:

   In this order:

   1.  One or more <street> elements (Section 2.37)

   2.  In any order:

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       *  <city> elements (Section 2.9)

       *  <region> elements (Section 2.32)

       *  <code> elements (Section 2.10)

       *  <country> elements (Section 2.11)

2.28.  <postamble>

   Gives text that appears at the bottom of a figure or table.

   This element appears as child element of: <figure> (Section 2.17),
   and <texttable> (Section 2.39).

   Content model:

   In any order:

   o  Text

   o  <xref> elements (Section 2.45)

   o  <eref> elements (Section 2.15)

   o  <iref> elements (Section 2.20)

   o  <cref> elements (Section 2.12)

   o  <spanx> elements (Section 2.36)

2.29.  <preamble>

   Gives text that appears at the top of a figure or table.

   This element appears as child element of: <figure> (Section 2.17),
   and <texttable> (Section 2.39).

   Content model:

   In any order:

   o  Text

   o  <xref> elements (Section 2.45)

   o  <eref> elements (Section 2.15)

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   o  <iref> elements (Section 2.20)

   o  <cref> elements (Section 2.12)

   o  <spanx> elements (Section 2.36)

2.30.  <reference>

   Represents a bibliographical reference.

   This element appears as child element of: <references>
   (Section 2.31).

   Content model:

   In this order:

   1.  One <front> element (Section 2.19)

   2.  Optional <seriesInfo> elements (Section 2.35)

   3.  Optional <format> elements (Section 2.18)

   4.  Optional <annotation> elements (Section 2.3)

2.30.1.  'anchor' attribute (mandatory)

   Document-wide unique identifier for this reference.  Usually, this
   will be used both to "label" the reference in the references section,
   and as an identifier in links to this reference entry.

   The value needs to be a valid XML "Name" (Section 2.3 of [XML]),
   additionally constrained to US-ASCII characters ([USASCII]).

2.30.2.  'target' attribute

   Holds the URI for the reference.

   Note that depending on the <seriesInfo> element, a URI might not be
   needed, nor desirable, as it can be automatically generated (for
   instance, for RFCs).

2.31.  <references>

   Contains a set of bibliographical references.

   In the early days of the RFC series, there was only one "References"
   section per RFC.  This convention was later changed to group

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   references into two sets, "Normative" and "Informative" as described
   in Section 4.8.6 of [RFCSTYLE]).  This vocabulary supports the split
   with the "title" attribute.

   This element appears as child element of: <back> (Section 2.7).

   Content model:

   One or more <reference> elements (Section 2.30)

2.31.1.  'title' attribute

   Provides the title for the References section (defaulting to
   "References").

   In general, the title should be either "Normative References" or
   "Informative References".

2.32.  <region>

   Provides the region name in a postal address.

   This element appears as child element of: <postal> (Section 2.27).

   Content model: only text content.

2.33.  <rfc>

   This is the root element of the xml2rfc vocabulary.

   Processors distinguish between RFC mode ("number" attribute being
   present) and Internet-Draft mode ("docName" attribute being present):
   it is invalid to specify both.  Setting neither "number" nor
   "docName" can be useful for producing other types of document but is
   out-of-scope for this specification.

   Content model:

   In this order:

   1.  One <front> element (Section 2.19)

   2.  One <middle> element (Section 2.23)

   3.  One optional <back> element (Section 2.7)

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2.33.1.  'category' attribute

   Document category (see Appendix A.1).

   Allowed values:

   o  "std"

   o  "bcp"

   o  "info"

   o  "exp"

   o  "historic"

2.33.2.  'consensus' attribute

   Affects the generated boilerplate.

   See [RFC5741] for more information.

   Allowed values:

   o  "no"

   o  "yes"

2.33.3.  'docName' attribute

   For Internet-Drafts, this specifies the draft name (which appears
   below the title).

   A processor should give an error if both the "docName" and "number"
   attributes are given in the <rfc> element.

   Note that the file extension is not part of the draft, so in general
   it should end with the current draft number ("-", plus two digits).

   Furthermore, it is good practice to disambiguate current editor
   copies from submitted drafts (for instance, by replacing the draft
   number with the string "latest").

   See Section 7 of [IDGUIDE] for further information.

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2.33.4.  'ipr' attribute

   Represents the Intellectual Property status of the document.  See
   Appendix A.2 for details.

   Allowed values:

   o  "full2026"

   o  "noDerivativeWorks2026"

   o  "none"

   o  "full3667"

   o  "noModification3667"

   o  "noDerivatives3667"

   o  "full3978"

   o  "noModification3978"

   o  "noDerivatives3978"

   o  "trust200811"

   o  "noModificationTrust200811"

   o  "noDerivativesTrust200811"

   o  "trust200902"

   o  "noModificationTrust200902"

   o  "noDerivativesTrust200902"

   o  "pre5378Trust200902"

2.33.5.  'iprExtract' attribute

   Identifies a single section within the document (by its 'anchor'
   attribute) for which extraction "as-is" is explicitly allowed (this
   is only relevant for historic values of the "ipr" attribute).

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2.33.6.  'number' attribute

   The number of the RFC to be produced.

   A processor should give an error if both the "docName" and "number"
   attributes are given in the <rfc> element.

2.33.7.  'obsoletes' attribute

   A comma-separated list of RFC _numbers_ or Internet-Draft names.

   Processors ought to parse the attribute value, so that incorrect
   references can be detected and, depending on output format,
   hyperlinks can be generated.  Also, the value ought to be reformatted
   to insert whitespace after each comma if not already present.

2.33.8.  'seriesNo' attribute

   When producing a document within document series (such as "STD"): the
   number within that series.

2.33.9.  'submissionType' attribute

   The document stream.

   See Section 2 of [RFC5741] for details.

   Allowed values:

   o  "IETF" (default)

   o  "IAB"

   o  "IRTF"

   o  "independent"

2.33.10.  'updates' attribute

   A comma-separated list of RFC _numbers_ or Internet-Draft names.

   Processors ought to parse the attribute value, so that incorrect
   references can be detected and, depending on output format,
   hyperlinks can be generated.  Also, the value ought to be reformatted
   to insert whitespace after each comma if not already present.

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2.33.11.  'xml:lang' attribute

   The natural language used in the document (defaults to "en").

   See Section 2.12 of [XML] for more information.

2.34.  <section>

   Represents a section (when inside a <middle> element) or an appendix
   (when inside a <back> element).

   Sub-sections are created by nesting <section> elements inside
   <section> elements.

   This element appears as child element of: <back> (Section 2.7),
   <middle> (Section 2.23), and <section> (Section 2.34).

   Content model:

   In this order:

   1.  In any order:

       *  <t> elements (Section 2.38)

       *  <figure> elements (Section 2.17)

       *  <texttable> elements (Section 2.39)

       *  <iref> elements (Section 2.20)

   2.  Optional <section> elements (Section 2.34)

2.34.1.  'anchor' attribute

   Document-wide unique identifier for this section.

   The value needs to be a valid XML "Name" (Section 2.3 of [XML]).

2.34.2.  'title' attribute (mandatory)

   The title of the section.

2.34.3.  'toc' attribute

   Determines whether the section is included in the Table Of Contents.

   The processor usually has defaults for whether a Table Of Contents

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   will be produced at all, and sections of which maximal depth will be
   included (frequently: 3). "include" and "exclude" allow overriding
   the processor's default behavior for the element they are specified
   on (they do not affect nested elements).

   Allowed values:

   o  "include"

   o  "exclude"

   o  "default" (default)

2.35.  <seriesInfo>

   Specifies the document series in which this document appears, and
   also specifies an identifier within that series.

   This element appears as child element of: <reference> (Section 2.30).

   Content model: this element does not have any contents.

2.35.1.  'name' attribute (mandatory)

   The name of the series.

   The following names trigger specific processing (such as for auto-
   generating links, and adding descriptions such as "work in
   progress"): "BCP", "FYI", "Internet-Draft", "RFC", and "STD".

2.35.2.  'value' attribute (mandatory)

   The identifier within the series specified by the "name" attribute.

   For BCPs, FYIs, RFCs, and STDs this is the number within the series.
   For Internet-Drafts, it is the full draft name (ending with the two-
   digit version number).

2.36.  <spanx>

   Wraps a piece of text, indicating special formatting styles.

   When generating plain text, processors usually emulate font changes
   using characters such as "*" and "_".

   The following styles are defined:

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   emph  Simple emphasis (this is the default).

   strong  Strong emphasis.

   verb  "Verbatim" text (usually displayed usign a monospaced font
      face).

   This element appears as child element of: <annotation> (Section 2.3),
   <c> (Section 2.8), <postamble> (Section 2.28), <preamble>
   (Section 2.29), and <t> (Section 2.38).

   Content model: only text content.

2.36.1.  'style' attribute

   The style to be used (defaults to "emph").

2.36.2.  'xml:space' attribute

   Determines whitespace handling.

   According to the DTD, the default value is "preserve".  Tests however
   show that it doesn't have any effect on processing; thus this
   attribute will be removed in future versions of the vocabulary.

   See also Section 2.10 of [XML].

   Allowed values:

   o  "default"

   o  "preserve" (default)

2.37.  <street>

   Provides a street address.

   This element appears as child element of: <postal> (Section 2.27).

   Content model: only text content.

2.38.  <t>

   Contains a paragraph of text.

   This element appears as child element of: <abstract> (Section 2.1),
   <list> (Section 2.22), <note> (Section 2.24), and <section>
   (Section 2.34).

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   Content model:

   In any order:

   o  Text

   o  <list> elements (Section 2.22)

   o  <figure> elements (Section 2.17)

   o  <xref> elements (Section 2.45)

   o  <eref> elements (Section 2.15)

   o  <iref> elements (Section 2.20)

   o  <cref> elements (Section 2.12)

   o  <spanx> elements (Section 2.36)

   o  <vspace> elements (Section 2.43)

2.38.1.  'anchor' attribute

   Document-wide unique identifier for this paragraph.

   The value needs to be a valid XML "Name" (Section 2.3 of [XML]).

2.38.2.  'hangText' attribute

   Holds the label ("hanging text") for items in lists using the
   "hanging" style (see Section 2.22.3).

2.39.  <texttable>

   Contains a table, consisting of an optional preamble, a header line,
   rows, an optional postamble, and an optional title.

   The number of columns in the table is determined by the number of
   <ttcol> elements.  The number of rows in the table is determined by
   the number of <c> elements divided by the number of columns.  There
   is no requirement that the number of <c> elements be evenly divisible
   by the number of columns.

   This element appears as child element of: <section> (Section 2.34).

   Content model:

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   In this order:

   1.  One optional <preamble> element (Section 2.29)

   2.  One or more <ttcol> elements (Section 2.41)

   3.  Optional <c> elements (Section 2.8)

   4.  One optional <postamble> element (Section 2.28)

2.39.1.  'align' attribute

   Determines the horizontal alignment of the table.

   Allowed values:

   o  "left"

   o  "center" (default)

   o  "right"

2.39.2.  'anchor' attribute

   Document-wide unique identifier for this table.

   Furthermore, the presence of this attribute causes the table to be
   numbered.

   The value needs to be a valid XML "Name" (Section 2.3 of [XML]).

2.39.3.  'style' attribute

   Selects which borders should be drawn, where

   o  "all" means borders around all table cells,

   o  "full" is like "all" except no horizontal lines between table rows
      (except below the column titles),

   o  "headers" adds just a separator between column titles and rows,
      and

   o  "none" means no borders at all.

   Allowed values:

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   o  "all"

   o  "none"

   o  "headers"

   o  "full" (default)

2.39.4.  'suppress-title' attribute

   Tables that have an "anchor" attribute will automatically get an
   autogenerated title (such as "Table 1"), even if the "title"
   attribute is absent.  Setting this attribute to "true" will prevent
   this.

   Allowed values:

   o  "true"

   o  "false" (default)

2.39.5.  'title' attribute

   The title for the table; this usually appears on a line below the
   table body.

2.40.  <title>

   Represents the document title.

   When this element appears in the <front> element of the current
   document, the title might also appear in page headers or footers.  If
   it's long (~40 characters), the "abbrev" attribute is used to specify
   an abbreviated variant.

   This element appears as child element of: <front> (Section 2.19).

   Content model: only text content.

2.40.1.  'abbrev' attribute

   Specifies an abbreviated variant of the document title.

2.41.  <ttcol>

   Contains a column heading in a table.

   This element appears as child element of: <texttable> (Section 2.39).

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   Content model: only text content.

2.41.1.  'align' attribute

   Determines the horizontal alignment within the table column.

   Allowed values:

   o  "left" (default)

   o  "center"

   o  "right"

2.41.2.  'width' attribute

   The desired column width (as integer 0..100 followed by "%").

2.42.  <uri>

   Contains a web address associated with the author.

   The contents should be a valid URI (see Section 3 of [RFC3986]).

   This element appears as child element of: <address> (Section 2.2).

   Content model: only text content.

2.43.  <vspace>

   This element can be used to force the inclusion of a single line
   break or multiple blank lines.

   Note that this is a purely presentational element and thus its use
   ought to be avoided.

   This element appears as child element of: <t> (Section 2.38).

   Content model: this element does not have any contents.

2.43.1.  'blankLines' attribute

   Number of blank lines to be inserted, where "0" indicates a single
   line break (defaults to "0").

   For paged output formats, no additional blank lines should be
   generated after a page break.

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2.44.  <workgroup>

   This element is used to specify the Working Group (IETF) or Research
   Group (IRTF) from which the document originates, if any.  The
   recommended format is the official name of the Working Group (with
   some capitalization).

   In Internet-Drafts, this is used in the upper left corner of the
   boilerplate, replacing the "Network Working Group" string.
   Formatting software can append the words "Working Group" or "Research
   Group", depending on the "submissionType" property on the <rfc>
   element (Section 2.33.9).

   This element appears as child element of: <front> (Section 2.19).

   Content model: only text content.

2.45.  <xref>

   Inserts a reference to a different part of a document.

   The generated text depends on whether the <xref> is empty (in which
   case the processor will try to generate a meaningful text fragment),
   and the nature of the referenced document part.

   Any element that allows the "anchor" attribute can be referenced,
   however there are restrictions with respect to the text content being
   generated.  For instance, a <t> can be a reference target, however,
   because paragraphs are not (visibly) numbered, the author will have
   to make sure that the prose is sufficient for a reader to understand
   what is being referred to.

   [[anchor2: This needs to be expanded with examples and with a
   discussion how the autogenerated text differs when <xref> is not
   empty]]

   This element appears as child element of: <annotation> (Section 2.3),
   <c> (Section 2.8), <postamble> (Section 2.28), <preamble>
   (Section 2.29), and <t> (Section 2.38).

   Content model: only text content.

2.45.1.  'format' attribute

   This attribute is used to control the format of the generated
   reference text.

   "counter"

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      Inserts a counter, such as the number of a section, figure, or
      table.

   "default"

      Inserts a text fragment that describes the referenced part
      completely, such as "Section 2", "Table 4", or "[XML]".

   "none"

      There will be no auto-generated text.

   "title"

      Inserts a title for the referenced element (usually obtained from
      the referenced element's "title" attribute; some processors also
      use the <title> child element or a <reference> target).

   Allowed values:

   o  "counter"

   o  "title"

   o  "none"

   o  "default" (default)

2.45.2.  'pageno' attribute

   Unused.

   It's unclear what the purpose of this attribute is; processors seem
   to ignore it and it never was documented.

   Allowed values:

   o  "true"

   o  "false" (default)

2.45.3.  'target' attribute (mandatory)

   Identifies the document component being referenced.

   The value needs to match the value of the "anchor" attribute of
   another element in the document.

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3.  Escaping for use in XML

   Text in XML can not use the literal characters "<" and "&", as they
   have special meaning to the XML processor (starting entities,
   elements, etc.).  Usually, these characters will need to be
   substituted by "&lt;" and "&amp;" (see Section 4.6 of [XML]).

   ">" does not require escaping, unless it appears in the sequence
   "]]>" (which indicates the end of a CDATA section, see below).

   Escaping the indivual characters can be a lot of work (when done
   manually), and also messes up alignment in artwork.  Another approach
   to escaping is to use CDATA sections ([XML], Section 2.7).  Within
   these, no further escaping is needed, except when the "end-of-CDATA"
   marker needs to be used (in that case, the CDATA section needs to be
   closed, and a new one needs to be started).

4.  Special Unicode Code Points

   Although the current RFC format does not allow non-ASCII Unicode
   characters ([UNICODE]), some of them can be used to enforce certain
   behaviors of formatters.

   For instance:

   non-breaking space (U+00A0)

      Represents a space character where no line break should happen.
      This is frequenly used in titles (by excluding certain space
      characters from the line breaking algorithm, the processor will
      use the remaining whitespace ocurrences for line breaks).

   non-breaking hyphen (U+2011)

      Similarly, this represents a hyphen character where nevertheless
      no line breaking ought to occur.

   word joiner (U+2060)

      Also called "zero width non-breaking space" -- can be used to
      disallow line breaking between two non-whitespace characters.

   Note that in order to use these characters by name, they need to be
   declared either in the Document Type Definition (DTD, [XML], Section
   2.9), or in the "internal subset" ([XML], Section 2.8), like that:

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   <?xml version="1.0"?>

   <!DOCTYPE rfc [

     <!-- declare nbsp and friends -->
     <!ENTITY nbsp    "&#xa0;">
     <!ENTITY nbhy    "&#x2011;">
     <!ENTITY wj      "&#x2060;">
   ]>

5.  Including Files

   This version of the vocabulary does not support an inclusion
   mechanism on it's own -- thus, a document always needs to be self-
   contained.

   That being said, some processors do support file inclusion using
   processing instructions (Section 2.6 of [XML]).

   Furthermore, XML itself allows inclusion of external content using
   the "internal subset" (Section 2.8 of [XML]).  Unfortunately, this
   requires declaring the external data in the DTD upfront.

   For instance:

   <?xml version="1.0"?>

   <!DOCTYPE rfc [

     <!-- allow later RFC2616 reference using "&rfc2616;" -->
     <!-- the data will be fetched from xml.resource.org -->
     <!ENTITY rfc2616 PUBLIC
     "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2616.xml">
   ]>

   ...declares the entity "rfc2616", which then can be used in the
   "references" section:

     <references>
       &rfc2616;
     </references>

   Note that this mechanism only works for well-formed XML fragments;
   thus any plain text that would need to be escaped in XML can't be
   included as-is.

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6.  Internationalization Considerations

   This format is based on [XML], thus does not have any issues
   representing arbitrary Unicode [UNICODE] characters in text content.

   However, the current canonical RFC format is restricted to US-ASCII
   [USASCII] characters ([RFC2223], Section 3).  Future versions are
   likely to relax this role, and it is expected that the vocabulary
   will be extended so that US-ACSII alternatives can be provided when
   that makes sense (for instance, in contact information).

7.  Security Considerations

   The "name" attribute on the <artwork> element (Section 2.5.4) can be
   used to derive a filename for saving to a local file system.
   Trusting this kind of information without pre-processing is a known
   security risk; see Section 4.3 of [RFC6266] for more information.

   Furthermore, the nature of XML, plus vocabulary features such as
   typed artwork, make it attractive to extract content from documents
   for further processing, such for the purpose of checking syntax, or
   computing/verifying examples.  In the latter case, care needs to be
   taken that only trusted content is processed.

   Furthermore, all security considerations related to XML processing
   are relevant as well (see Section 7 of [RFC3470]).

8.  IANA Considerations

8.1.  Internet Media Type Registration

   IANA maintains the registry of Internet media types [BCP13] at
   <http://www.iana.org/assignments/media-types>.

   This document serves as the specification for the Internet media type
   "application/rfc+xml".  The following is to be registered with IANA.

   Type name:  application

   Subtype name:  rfc+xml

   Required parameters:  There are no required parameters.

   Optional parameters:  "charset": This parameter has identical
      semantics as the charset parameter of the "application/xml" media
      type specified in [RFC3023].

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   Encoding considerations:  Identical to those of "application/xml" as
      described in Section 3.2 of [RFC3023].

   Security considerations:  As defined in Section 7.  In addition, as
      this media type uses the "+xml" convention, it inherits the
      security considerations described in Section 10 of [RFC3023].

   Interoperability considerations:  N/A

   Published specification:  This specification.

   Applications that use this media type:  Applications that either
      transform xml2rfc to output formats such as plain text or HTML,
      plus additional analysis tools.

   Fragment identifier considerations:  The "anchor" attribute is used
      for assigning document-wide unique identifiers that can be uses as
      shorthand pointers, as described in Section 2.8 of [XPOINTER].

   Additional information:

      Deprecated alias names for this type:  None.

      Magic number(s):  As specified for "application/xml" in Section
         3.2 of [RFC3023].

      File extension(s):  .xml or .rfcxml when disambiguation from other
         XML files is needed

      Macintosh file type code(s):  TEXT

   Person & email address to contact for further information:  See
      Authors Section.

   Intended usage:  COMMON

   Restrictions on usage:  N/A

   Author:  See Authors Section.

   Change controller:  RFC Series Editor (rse@rfc-editor.org)

9.  Acknowledgments

   Thanks to everybody who reviewed this document and provided feedback
   and/or specification text, in particular Brian Carpenter, Tony
   Hansen, Paul Hoffman, Henrik Levkowetz, Alice Russo, Tom Taylor, Jim
   Schaad, and Nico Williams.

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   We also thank Marshall T. Rose for both the original design and the
   reference implementation of the "xml2rfc" formatter.

10.  References

10.1.  Normative References

   [XML]        Maler, E., Yergeau, F., Paoli, J., Sperberg-McQueen, M.,
                and T. Bray, "Extensible Markup Language (XML) 1.0
                (Fifth Edition)", W3C Recommendation REC-xml-20081126,
                November 2008,
                <http://www.w3.org/TR/2008/REC-xml-20081126/>.

                Latest version available at <http://www.w3.org/TR/xml>.

10.2.  Informative References

   [BCP13]      Freed, N., Klensin, J., and T. Hansen, "Media Type
                Specifications and Registration Procedures", BCP 13,
                RFC 6838, January 2013.

   [IDGUIDE]    Housley, R., "Guidelines to Authors of Internet-Drafts",
                December 2010,
                <http://www.ietf.org/id-info/guidelines.html>.

   [JING]       Thai Open Source Software Center Ltd, "Jing - A RELAX NG
                validator in Java", W3C Recommendation REC-xptr-
                framework-20030325, 2008,
                <http://www.thaiopensource.com/relaxng/jing.html>.

                Downloads:
                <https://code.google.com/p/jing-trang/downloads/list>.

   [RFC2026]    Bradner, S., "The Internet Standards Process -- Revision
                3", BCP 9, RFC 2026, October 1996.

   [RFC2046]    Freed, N. and N. Borenstein, "Multipurpose Internet Mail
                Extensions (MIME) Part Two: Media Types", RFC 2046,
                November 1996.

   [RFC2223]    Postel, J. and J. Reynolds, "Instructions to RFC
                Authors", RFC 2223, October 1997.

   [RFC2397]    Masinter, L., "The "data" URL scheme", RFC 2397,
                August 1998.

   [RFC2629]    Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
                June 1999.

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   [RFC3023]    Murata, M., St. Laurent, S., and D. Kohn, "XML Media
                Types", RFC 3023, January 2001.

   [RFC3470]    Hollenbeck, S., Rose, M., and L. Masinter, "Guidelines
                for the Use of Extensible Markup Language (XML) within
                IETF Protocols", BCP 70, RFC 3470, January 2003.

   [RFC3966]    Schulzrinne, H., "The tel URI for Telephone Numbers",
                RFC 3966, December 2004.

   [RFC3986]    Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
                Resource Identifier (URI): Generic Syntax", STD 66,
                RFC 3986, January 2005.

   [RFC5598]    Crocker, D., "Internet Mail Architecture", RFC 5598,
                July 2009.

                PDF version: <http://www.rfc-editor.org/rfc/rfc5598.pdf>

   [RFC5741]    Daigle, L. and O. Kolkman, "RFC Streams, Headers, and
                Boilerplates", RFC 5741, December 2009.

   [RFC6068]    Duerst, M., Masinter, L., and J. Zawinski, "The 'mailto'
                URI Scheme", RFC 6068, October 2010.

   [RFC6266]    Reschke, J., "Use of the Content-Disposition Header
                Field in the Hypertext Transfer Protocol (HTTP)",
                RFC 6266, June 2011.

   [RFCPOLICY]  RFC Editor, "RFC Editorial Guidelines and Procedures",
                February 2012, <http://www.rfc-editor.org/policy.html>.

   [RFCSTYLE]   Heather, H. and S. Ginoza, "RFC Style Guide",
                draft-iab-styleguide-02 (work in progress), April 2014.

   [RNC]        Clark, J., "RELAX NG Compact Syntax", OASIS ,
                November 2002, <http://www.oasis-open.org/committees/
                relax-ng/compact-20021121.html>.

   [TLP2.0]     IETF Trust, "Legal Provisions Relating to IETF
                Documents", February 2009,
                <http://trustee.ietf.org/license-info/IETF-TLP-2.htm>.

   [TLP3.0]     IETF Trust, "Legal Provisions Relating to IETF
                Documents", September 2009,
                <http://trustee.ietf.org/license-info/IETF-TLP-3.htm>.

   [TLP4.0]     IETF Trust, "Legal Provisions Relating to IETF

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                Documents", December 2009,
                <http://trustee.ietf.org/license-info/IETF-TLP-4.htm>.

   [UNICODE]    The Unicode Consortium, "The Unicode Standard, Version
                6.3.0", September 2013,
                <http://www.unicode.org/versions/Unicode6.3.0/>.

   [USASCII]    American National Standards Institute, "Coded Character
                Set -- 7-bit American Standard Code for Information
                Interchange", ANSI X3.4, 1986.

   [XINCLUDE]   Marsh, J., Orchard, D., and D. Veillard, "XML Inclusions
                (XInclude) Version 1.0 (Second Edition)", W3C
                Recommendation REC-xinclude-20061115, November 2006,
                <http://www.w3.org/TR/2006/REC-xinclude-20061115/>.

                Latest version available at
                <http://www.w3.org/TR/xinclude/>.

   [XPOINTER]   Grosso, P., Maler, E., Marsh, J., and N. Walsh,
                "XPointer Framework", W3C Recommendation REC-xptr-
                framework-20030325, March 2003,
                <http://www.w3.org/TR/2003/
                REC-xptr-framework-20030325/>.

                Latest version available at
                <http://www.w3.org/TR/xptr-framework/>.

Appendix A.  Front Page Generation

A.1.  The /rfc/@category Attribute

   For RFCs, the "category" determines the "maturity level" (see Section
   4 of [RFC2026]).  The allowed values are "std" for "Standards Track",
   "bcp" for "BCP", "info" for "Informational", "exp" for
   "Experimental", and "historic" for "Historic".

   For Internet-Drafts, the category attribute is not needed, but will
   appear on the front page as "Intended Status".  Supplying this
   information can be useful to reviewers.

A.2.  The /rfc/@ipr Attribute

   This attribute value can take a long list of values, each of which
   describes an IPR policy for the document.  This attribute's values
   are not the result of a grand plan, but remain simply for historic
   reasons.  Of these values, only a few are currently in use; all
   others are supported by the various tools for backwards compatibility

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   with old source files.

      Note: some variations of the boilerplate are selected based on the
      document's date; therefore it is important to specify the "year",
      "month" and "day" attributes of the "<date>" element when
      archiving the XML source of an Internet-Draft on the day of
      submission.

   _Disclaimer: THIS ONLY PROVIDES IMPLEMENTATION INFORMATION.  IF YOU
   NEED LEGAL ADVICE, PLEASE CONTACT A LAWYER._ For further information,
   refer to <http://trustee.ietf.org/docs/IETF-Copyright-FAQ.pdf>.

   For the current "Status Of This Memo" text, the "submissionType"
   attribute determines whether a statement about "Code Components" is
   inserted (which is the case for the value "IETF", which is the
   default).  Other values, such as "independent", suppress this part of
   the text.

A.2.1.  Current Values: '*trust200902'

   The name for these values refers to the "IETF TRUST Legal Provisions
   Relating to IETF Documents", sometimes simply called the "TLP, that
   went into effect on February 15, 2009 ([TLP2.0]).  Updates to this
   document were published on September 12, 2009 ([TLP3.0]) and on
   December 28, 2009 ([TLP4.0]), modifying the license for code
   components (see <http://trustee.ietf.org/license-info/> for further
   information).  The actual text is located in Section 6 ("Text To Be
   Included in IETF Documents") of these documents.

   The tools will automatically produce the "correct" text depending on
   the document's date information (see above):

   +----------+--------------------------------+
   | TLP      | starting with publication date |
   +----------+--------------------------------+
   | [TLP3.0] | 2009-11-01                     |
   | [TLP4.0] | 2010-04-01                     |
   +----------+--------------------------------+

A.2.1.1.  trust200902

   This should be the default, unless one of the more specific
   '*trust200902' values is a better fit.  It produces the text in
   Sections 6.a and 6.b of the TLP.

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A.2.1.2.  noModificationTrust200902

   This produces additional text from Section 6.c.i of the TLP:

      This document may not be modified, and derivative works of it may
      not be created, except to format it for publication as an RFC or
      to translate it into languages other than English.

      Note: this clause is incompatible with RFCs that are published on
      the Standards Track.

A.2.1.3.  noDerivativesTrust200902

   This produces the additional text from Section 6.c.ii of the TLP:

      This document may not be modified, and derivative works of it may
      not be created, and it may not be published except as an Internet-
      Draft.

      Note: this clause is incompatible with RFCs.

A.2.1.4.  pre5378Trust200902

   This produces the additional text from Section 6.c.iii of the TLP,
   frequently called the "pre-5378 escape clause":

      This document may contain material from IETF Documents or IETF
      Contributions published or made publicly available before November
      10, 2008.  The person(s) controlling the copyright in some of this
      material may not have granted the IETF Trust the right to allow
      modifications of such material outside the IETF Standards Process.
      Without obtaining an adequate license from the person(s)
      controlling the copyright in such materials, this document may not
      be modified outside the IETF Standards Process, and derivative
      works of it may not be created outside the IETF Standards Process,
      except to format it for publication as an RFC or to translate it
      into languages other than English.

   See Section 4 of
   <http://trustee.ietf.org/docs/IETF-Copyright-FAQ.pdf> for further
   information about when to use this value.

      Note: this text appears under "Copyright Notice", unless the
      document was published before November 2009, in which case it
      appears under "Status Of This Memo".

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A.2.2.  Historic Values

A.2.2.1.  Historic Values: '*trust200811'

   The attribute values "trust200811", "noModificationTrust200811" and
   "noDerivativesTrust200811" are similar to their "trust200902"
   counterparts, except that they use text specified in <http://
   trustee.ietf.org/license-info/archive/
   IETF-Trust-License-Policy_11-10-08.pdf>.

A.2.2.2.  Historic Values: '*3978'

   The attribute values "full3978", "noModification3978" and
   "noDerivatives3978" are similar to their counterparts above, except
   that they use text specified in RFC 3978 (March 2005).

A.2.2.3.  Historic Values: '*3667'

   The attribute values "full3667", "noModification3667" and
   "noDerivatives3667" are similar to their counterparts above, except
   that they use text specified in RFC 3667 (February 2004).

A.2.2.4.  Historic Values: '*2026'

   The attribute values "full2026" and "noDerivativeWorks2026" are
   similar to their counterparts above, except that they use text
   specified in RFC 2026 (October 1996).

   The special value "none" was also used back then, and denied the IETF
   any rights beyond publication as Internet-Draft.

Appendix B.  Changes from RFC 2629 ('v1')

   [[v1diff: See <http://greenbytes.de/tech/webdav/
   draft-reschke-xml2rfc-02.html#rfc.section.E> for a comparison of the
   schemata.]]

B.1.  Removed Elements

   The <appendix> element has been removed; to generate an appendix,
   place a <section> inside <back>.

B.2.  Changed Defaults

   Many attributes have lost their "default" value; this is to avoid
   having document semantics differ based on whether a DTD was specified
   and evaluated.  Processors will handle absent values the way the
   default value was specified before.

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B.3.  Changed Elements

   <artwork>: Has a set of new attributes: "name", "type", "src",
   "align", "alt", "width", and "height".  (Section 2.5)

   <author>: The <organization> element is now optional.  The "role"
   attribute was added.  (Section 2.6)

   <country>: The requirement to use ISO 3166 codes was removed.
   (Section 2.11)

   <date>: All attributes are now optional.  (Section 2.13)

   <figure>: Has a set of new attributes: "suppress-title", "src",
   "align", "alt", "width", and "height".  (Section 2.17)

   <iref>: Has a new "primary" attribute.  (Section 2.20)

   <list>: The "style" attribute isn't restricted to a set of enumerated
   values anymore.  The "hangIndent" and "counter" attributes have been
   added.  (Section 2.22)

   <rfc>: The "ipr" attribute has gained additional values.  The
   attributes "consensus", "iprExtract", "submissionType", and "xml:
   lang" have been added.  (Section 2.33)

   <reference>: <annotation> allows adding prose to a reference.  The
   "anchor" attribute has been made mandatory.  (Section 2.30)

   <references>: Can now appear multiple times, and carry a "title"
   attribute (so that normative and informative references can be
   split).  (Section 2.31)

   <section>: The new "toc" attribute controls whether it will appear in
   the Table Of Contents. <iref> can now appear as direct child element.
   (Section 2.34)

   <t>: The "anchor" attribute can now be used as well, however there
   are restrictions on how they can be referred to.  (Section 2.38)

B.4.  New Elements

   The following elements have been added: <annotation> (Section 2.3),
   <c> (Section 2.8), <cref> (Section 2.12), <format> (Section 2.18),
   <spanx> (Section 2.36), <texttable> (Section 2.39).

Appendix C.  Relax NG Schema

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   namespace a = "http://relaxng.org/ns/compatibility/annotations/1.0"

   rfc =
     element rfc {
       attribute number { text }?,
       [ a:defaultValue = "" ] attribute obsoletes { text }?,
       [ a:defaultValue = "" ] attribute updates { text }?,
       attribute category { "std" | "bcp" | "info" | "exp" | "historic"
   }?,
       attribute consensus { "no" | "yes" }?,
       attribute seriesNo { text }?,
       attribute ipr {
         "full2026"
         | "noDerivativeWorks2026"
         | "none"
         | "full3667"
         | "noModification3667"
         | "noDerivatives3667"
         | "full3978"
         | "noModification3978"
         | "noDerivatives3978"
         | "trust200811"
         | "noModificationTrust200811"
         | "noDerivativesTrust200811"
         | "trust200902"
         | "noModificationTrust200902"
         | "noDerivativesTrust200902"
         | "pre5378Trust200902"
       }?,
       attribute iprExtract { xsd:IDREF }?,
       [ a:defaultValue = "IETF" ]
       attribute submissionType {
         "IETF" | "IAB" | "IRTF" | "independent"
       }?,
       attribute docName { text }?,
       [ a:defaultValue = "en" ] attribute xml:lang { text }?,
       front,
       middle,
       back?
     }
   front =
     element front {
       title, author+, date, area*, workgroup*, keyword*, abstract?,
   note*
     }
   title =
     element title {
       attribute abbrev { text }?,

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       text
     }
   author =
     element author {
       attribute initials { text }?,
       attribute surname { text }?,
       attribute fullname { text }?,
       attribute role { "editor" }?,
       organization?,
       address?
     }
   organization =
     element organization {
       attribute abbrev { text }?,
       text
     }
   address = element address { postal?, phone?, facsimile?, email?,
   uri? }
   postal = element postal { street+, (city | region | code | country)*
   }
   street = element street { text }
   city = element city { text }
   region = element region { text }
   code = element code { text }
   country = element country { text }
   phone = element phone { text }
   facsimile = element facsimile { text }
   email = element email { text }
   uri = element uri { text }
   date =
     element date {
       attribute day { text }?,
       attribute month { text }?,
       attribute year { text }?,
       empty
     }
   area = element area { text }
   workgroup = element workgroup { text }
   keyword = element keyword { text }
   abstract = element abstract { t+ }
   note =
     element note {
       attribute title { text },
       t+
     }
   middle = element middle { section+ }
   section =
     element section {

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       attribute anchor { xsd:ID }?,
       attribute title { text },
       [ a:defaultValue = "default" ]
       attribute toc { "include" | "exclude" | "default" }?,
       (t | figure | texttable | iref)*,
       section*
     }
   t =
     element t {
       attribute anchor { xsd:ID }?,
       attribute hangText { text }?,
       (text
        | \list
        | figure
        | xref
        | eref
        | iref
        | cref
        | spanx
        | vspace)*
     }
   \list =
     element list {
       attribute style { text }?,
       attribute hangIndent { text }?,
       attribute counter { text }?,
       t+
     }
   xref =
     element xref {
       attribute target { xsd:IDREF },
       [ a:defaultValue = "false" ] attribute pageno { "true" | "false"
   }?,
       [ a:defaultValue = "default" ]
       attribute format { "counter" | "title" | "none" | "default" }?,
       text
     }
   eref =
     element eref {
       attribute target { text },
       text
     }
   iref =
     element iref {
       attribute item { text },
       [ a:defaultValue = "" ] attribute subitem { text }?,
       [ a:defaultValue = "false" ]
       attribute primary { "true" | "false" }?,

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       empty
     }
   cref =
     element cref {
       attribute anchor { xsd:ID }?,
       attribute source { text }?,
       text
     }
   spanx =
     element spanx {
       [ a:defaultValue = "preserve" ]
       attribute xml:space { "default" | "preserve" }?,
       [ a:defaultValue = "emph" ] attribute style { text }?,
       text
     }
   vspace =
     element vspace {
       [ a:defaultValue = "0" ] attribute blankLines { text }?,
       empty
     }
   figure =
     element figure {
       attribute anchor { xsd:ID }?,
       [ a:defaultValue = "" ] attribute title { text }?,
       [ a:defaultValue = "false" ]
       attribute suppress-title { "true" | "false" }?,
       attribute src { text }?,
       [ a:defaultValue = "left" ]
       attribute align { "left" | "center" | "right" }?,
       [ a:defaultValue = "" ] attribute alt { text }?,
       [ a:defaultValue = "" ] attribute width { text }?,
       [ a:defaultValue = "" ] attribute height { text }?,
       iref*,
       preamble?,
       artwork,
       postamble?
     }
   preamble =
     element preamble { (text | xref | eref | iref | cref | spanx)* }
   artwork =
     element artwork {
       [ a:defaultValue = "preserve" ]
       attribute xml:space { "default" | "preserve" }?,
       [ a:defaultValue = "" ] attribute name { text }?,
       [ a:defaultValue = "" ] attribute type { text }?,
       attribute src { text }?,
       [ a:defaultValue = "left" ]
       attribute align { "left" | "center" | "right" }?,

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       [ a:defaultValue = "" ] attribute alt { text }?,
       [ a:defaultValue = "" ] attribute width { text }?,
       [ a:defaultValue = "" ] attribute height { text }?,
       text*
     }
   postamble =
     element postamble { (text | xref | eref | iref | cref | spanx)* }
   texttable =
     element texttable {
       attribute anchor { xsd:ID }?,
       [ a:defaultValue = "" ] attribute title { text }?,
       [ a:defaultValue = "false" ]
       attribute suppress-title { "true" | "false" }?,
       [ a:defaultValue = "center" ]
       attribute align { "left" | "center" | "right" }?,
       [ a:defaultValue = "full" ]
       attribute style { "all" | "none" | "headers" | "full" }?,
       preamble?,
       ttcol+,
       c*,
       postamble?
     }
   ttcol =
     element ttcol {
       attribute width { text }?,
       [ a:defaultValue = "left" ]
       attribute align { "left" | "center" | "right" }?,
       text
     }
   c = element c { (text | xref | eref | iref | cref | spanx)* }
   back = element back { references*, section* }
   references =
     element references {
       [ a:defaultValue = "References" ] attribute title { text }?,
       reference+
     }
   reference =
     element reference {
       attribute anchor { xsd:ID },
       attribute target { text }?,
       front,
       seriesInfo*,
       format*,
       annotation*
     }
   seriesInfo =
     element seriesInfo {
       attribute name { text },

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       attribute value { text },
       empty
     }
   format =
     element format {
       attribute target { text }?,
       attribute type { text },
       attribute octets { text }?,
       empty
     }
   annotation =
     element annotation { (text | xref | eref | iref | cref | spanx)* }
   start = rfc

   (This schema was derived from version 1.3.6 of the xml2rfc DTD
   ('Document Type Definition', [XML], Section 2.8), available from <htt
   p://svn.tools.ietf.org/svn/tools/xml2rfc/vocabulary/v2/03/
   xml2rfcv2.dtd>).

C.1.  Checking Validity

   The validity of XML files can be checked with any tool that supports
   Relax NG ([RNC]).  The reference implementation is the Java-based,
   open sourced "JING" ([JING]).

   To use JING, download the latest ZIP file from the downloads page
   (currently <https://code.google.com/p/jing-trang/downloads/
   detail?name=jing-20091111.zip>), extract the archive, copy "jing.jar"
   from the "bin" folder, and make sure Java is installed).

   To check a file "test.xml" using the RNC file "schema.rnc", run (from
   a command line prompt):

   java -jar jing.jar -c schema.rnc test.xml

   In good Unix tradition, no output means the file is valid.

Appendix D.  Proposed Future Changes for 'v3'

   Discussion of "v3" changes takes place on the rfc-interest mailing
   list (rfc-interest@rfc-editor.org), which has its home page at
   <http://www.rfc-editor.org/mailman/listinfo/rfc-interest>.  See also
   <https://www.rfc-editor.org/rse/wiki/doku.php?id=design:xml-tags> for
   a related Wiki page.

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D.1.  Contact Information

   If contact information is changed to allow non-ASCII characters: add
   a place for a ASCII fallback (probably just for the author names).

   The content model for <postal> ought to be more strict to allow at
   most one of <city>, <region>, <code>, and <country>.

   It should be possible to have multiple <email> and <uri> elements
   (see also <http://trac.tools.ietf.org/tools/xml2rfc/trac/ticket/36>).

   <facsimile> looks outdated, while a container for IM (messaging) URIs
   is missing.  Maybe this area needs to be aligned with vCard.

   Section 4.11 of [RFCSTYLE] hints at a "Contributors" Section that
   could supply contact information similar to the one in the auto-
   generated "Authors' Address" Section.  Consider how to capture
   contributor contact information (probably not using <author> to avoid
   confusion).  Furthermore, consider ways to augment the contact
   information section with prose.

D.2.  Figures

   Cleanup the set of overlapping attributes between <figure> and
   <artwork>.

   For artwork that consists of a sequence of items (such as messages in
   a protocol example), it would be good if a <figure> element could
   contain multiple <artwork> elements (to assist code to find good
   places for page breaks).

   Extend <figure> to support different types of artwork (such as by
   specifying certain type attribute values, see <http://greenbytes.de/
   tech/webdav/rfc2629xslt/rfc2629xslt.html#artwork.types>), and also
   avoid having to markup code (such as ABNF) as "artwork".

   It would be good if "code components" could be marked as such.

   Finally, even in preformatted text use of markup could be useful to
   support (a) references, or (b) highlighting the important bits (<http
   ://greenbytes.de/tech/webdav/rfc2629xslt/
   rfc2629xslt.html#ext-rfc2629.artwork>).

D.3.  Linking

   Extend <xref> so that subsection/anchors can be specified (see <http:
   //greenbytes.de/tech/webdav/rfc2629xslt/
   rfc2629xslt.html#ext-rfc2629.xref>).

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   Remove the "pageno" attribute which seems to be both undocumented and
   non-functional.

D.4.  Lists

   Allow multiple paragraphs in list items; eliminating the need to use
   <vspace> -- this could be achieved by adding a list item container
   element ("<lt>", see <http://greenbytes.de/tech/webdav/rfc2629xslt/
   rfc2629xslt.html#ext.element.lt> and
   <http://www.ietf.org/mail-archive/web/xml2rfc/current/
   msg02010.html>).

   Add support for a "dictionary" style; eliminating the need to combine
   "hanging" with <vspace> to force new lines (see thread around <http:/
   /www.rfc-editor.org/pipermail/rfc-interest/2013-December/
   005876.html>).

D.5.  References

   Allow overriding the "anchor" attribute of an included <reference>
   element.

   Add a way to add prose to a reference that avoids abuse of
   <seriesInfo>.

   Allow <reference>s that identify a document set such as a BCP.

   Deprecate or remove the <format> element; right now it's not used for
   the generation of the plain text document anyway.

   The "anchor" attribute is optional because it is not needed when
   using numeric references (symrefs processing instruction), and the
   reference actually is not in use.  This is an edge case that doesn't
   need special support in the vocabulary and thus should be removed.

D.6.  Archival Considerations

   When this vocabulary becomes the canonical RFC format, it will need
   to be able to capture all generated information, such as section/
   figure/table numbers, plus any auto-generated boilerplate (copyright
   statements etc.).

D.7.  Document Metadata

   Extend the concept of language tagging to at least examples and
   contact information to address potential japanese/chinese font
   confusion.

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   Provide a way to indicate the intended level on the standards track.

   Include feedback information in a way so that generated documents can
   provide usable feedback links (see <http://greenbytes.de/tech/webdav/
   rfc2629xslt/rfc2629xslt.html#ext.element.feedback>).

D.8.  Including Material

   As discussed in Section 5, file inclusion currently uses out-of-the-
   box XML mechanisms or processor-specific directives.

   We need to decide whether the vocabulary should have its own
   inclusion mechanism, or whether it would be better to use a generic
   solution such as [XINCLUDE] instead.

D.9.  Misc.

   Make the <date> element optional; all of its content is optional
   already.

   <spanx> has both a weird whitespace model ("preserve") and
   problematic styling.  Consider to deprecate it in favor of elements
   such as <b>, <i>, and <tt>.

   Indented paragraphs currently can be created by abusing the <list>.
   It would be good to have a special element for this purpose.

   Provide a special element for inserting block quotes (<http://
   greenbytes.de/tech/webdav/rfc2629xslt/
   rfc2629xslt.html#ext.element.blockquote>).

   The content model for <cref> should be extended to allow more flow
   elements, such as <xref> and <eref>.

   Section titles should really be elements, not attributes (this would
   allow them to contain markup).

   Text tables are currently very constrained.  For instance, it would
   be good if alignment of headers and table cells could be de-coupled
   (<http://trac.tools.ietf.org/tools/xml2rfc/trac/ticket/69>).

   Counters are currently restricted to lists, figures, and tables.
   Maybe there should be a generic mechanism that is not directly tied
   to other elements
   (<http://trac.tools.ietf.org/tools/xml2rfc/trac/ticket/68>).

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Index

   A
      abbrev attribute
         in organization element  20
         in title element  32
      abstract element  4
         inside front  16
      address element  4
         inside author  9
      align attribute
         in artwork element  7
         in figure element  13
         in texttable element  31
         in ttcol element  33
      alt attribute
         in artwork element  7
         in figure element  14
      anchor attribute
         in cref element  11
         in figure element  14
         in reference element  22
         in section element  27
         in t element  30
         in texttable element  31
      annotation element  5
         inside reference  22
      application/rfc+xml Media Type  38
      area element  6
         inside front  16
      artwork element  6
         align attribute  7
         alt attribute  7
         height attribute  7
         inside figure  13
         name attribute  7
         src attribute  7
         type attribute  8
         width attribute  8
         xml:space attribute  8
      Attributes
         abbrev  20, 32
         align  7, 13, 31, 33
         alt  7, 14
         anchor  11, 14, 22, 27, 30-31
         blankLines  33
         category  24
         consensus  24

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         counter  17
         day  12
         docName  24
         format  34
         fullname  9
         hangIndent  17
         hangText  30
         height  7, 14
         initials  9
         ipr  25
         iprExtract  25
         item  16
         month  12
         name  7, 28
         number  26
         obsoletes  26
         octets  15
         pageno  35
         primary  16
         role  9
         seriesNo  26
         source  11
         src  7, 14
         style  18, 29, 31
         subitem  17
         submissionType  26
         suppress-title  14, 32
         surname  9
         target  13, 15, 22, 35
         title  14, 20, 23, 27, 32
         toc  27
         type  8, 15
         updates  26
         value  28
         width  8, 15, 33
         xml:lang  27
         xml:space  8, 29
         year  12
      author element  8
         fullname attribute  9
         initials attribute  9
         inside front  15
         role attribute  9
         surname attribute  9

   B
      back element  9
         inside rfc  23

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      blankLines attribute
         in vspace element  33

   C
      c element  10
         inside texttable  31
      category attribute
         in rfc element  24
      city element  10
         inside postal  21
      code element  10
         inside postal  21
      consensus attribute
         in rfc element  24
      counter attribute
         in list element  17
      country element  11
         inside postal  21
      cref element  11
         anchor attribute  11
         inside annotation  5
         inside c  10
         inside postamble  21
         inside preamble  22
         inside t  30
         source attribute  11

   D
      date element  11
         day attribute  12
         inside front  15
         month attribute  12
         year attribute  12
      day attribute
         in date element  12
      docName attribute
         in rfc element  24

   E
      Elements
         abstract  4, 16
         address  4, 9
         annotation  5, 22
         area  6, 16
         artwork  6, 13
         author  8, 15
         back  9, 23
         c  10, 31

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         city  10, 21
         code  10, 21
         country  11, 21
         cref  5, 10-11, 21-22, 30
         date  11, 15
         email  5, 12
         eref  5, 10, 12, 21, 30
         facsimile  5, 13
         figure  13, 27, 30
         format  15, 22
         front  15, 22-23
         iref  5, 10, 13, 16, 21-22, 27, 30
         keyword  16-17
         list  17, 30
         middle  19, 23
         note  16, 19
         organization  9, 20
         phone  5, 20
         postal  5, 20
         postamble  13, 21, 31
         preamble  13, 21, 31
         reference  22-23
         references  10, 22
         region  21, 23
         rfc  23
         section  10, 19, 27
         seriesInfo  22, 28
         spanx  5, 10, 21-22, 28, 30
         street  20, 29
         t  4, 17, 19, 27, 29
         texttable  27, 30
         title  15, 32
         ttcol  31-32
         uri  5, 33
         vspace  30, 33
         workgroup  16, 34
         xref  5, 10, 21, 30, 34
      email element  12
         inside address  5
      eref element  12
         inside annotation  5
         inside c  10
         inside postamble  21
         inside preamble  21
         inside t  30
         target attribute  13

   F

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      facsimile element  13
         inside address  5
      figure element  13
         align attribute  13
         alt attribute  14
         anchor attribute  14
         height attribute  14
         inside section  27
         inside t  30
         src attribute  14
         suppress-title attribute  14
         title attribute  14
         width attribute  15
      format attribute
         in xref element  34
      format element  15
         inside reference  22
         octets attribute  15
         target attribute  15
         type attribute  15
      front element  15
         inside reference  22
         inside rfc  23
      fullname attribute
         in author element  9

   H
      hangIndent attribute
         in list element  17
      hangText attribute
         in t element  30
      height attribute
         in artwork element  7
         in figure element  14

   I
      initials attribute
         in author element  9
      ipr attribute
         '*2026'  45
         '*3667'  45
         '*3978'  45
         '*trust200811'  45
         '*trust200902'  43
         'noDerivativesTrust200902'  44
         'noModificationTrust200902'  44
         'pre5378Trust200902'  44
         'trust200902'  43

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         in rfc element  25
      iprExtract attribute
         in rfc element  25
      iref element  16
         inside annotation  5
         inside c  10
         inside figure  13
         inside postamble  21
         inside preamble  22
         inside section  27
         inside t  30
         item attribute  16
         primary attribute  16
         subitem attribute  17
      item attribute
         in iref element  16

   K
      keyword element  17
         inside front  16

   L
      list element  17
         counter attribute  17
         hangIndent attribute  17
         inside t  30
         style attribute  18
      list styles
         empty  18
         format ...  18
         hanging  18
         letters  18
         numbers  18
         symbols  18

   M
      Media Type
         application/rfc+xml  38
      middle element  19
         inside rfc  23
      month attribute
         in date element  12

   N
      name attribute
         in artwork element  7
         in seriesInfo element  28
      note element  19

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         inside front  16
         title attribute  20
      number attribute
         in rfc element  26

   O
      obsoletes attribute
         in rfc element  26
      octets attribute
         in format element  15
      organization element  20
         abbrev attribute  20
         inside author  9

   P
      pageno attribute
         in xref element  35
      phone element  20
         inside address  5
      postal element  20
         inside address  5
      postamble element  21
         inside figure  13
         inside texttable  31
      preamble element  21
         inside figure  13
         inside texttable  31
      primary attribute
         in iref element  16

   R
      reference element  22
         anchor attribute  22
         inside references  23
         target attribute  22
      references element  22
         inside back  10
         title attribute  23
      region element  23
         inside postal  21
      rfc element  23
         category attribute  24
         consensus attribute  24
         docName attribute  24
         ipr attribute  25
         iprExtract attribute  25
         number attribute  26
         obsoletes attribute  26

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         seriesNo attribute  26
         submissionType attribute  26
         updates attribute  26
         xml:lang attribute  27
      role attribute
         in author element  9

   S
      section element  27
         anchor attribute  27
         inside back  10
         inside middle  19
         inside section  27
         title attribute  27
         toc attribute  27
      seriesInfo element  28
         inside reference  22
         name attribute  28
         value attribute  28
      seriesNo attribute
         in rfc element  26
      source attribute
         in cref element  11
      spanx element  28
         inside annotation  5
         inside c  10
         inside postamble  21
         inside preamble  22
         inside t  30
         style attribute  29
         xml:space attribute  29
      src attribute
         in artwork element  7
         in figure element  14
      street element  29
         inside postal  20
      style attribute
         in list element  18
         in spanx element  29
         in texttable element  31
      subitem attribute
         in iref element  17
      submissionType attribute
         in rfc element  26
      suppress-title attribute
         in figure element  14
         in texttable element  32
      surname attribute

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         in author element  9

   T
      t element  29
         anchor attribute  30
         hangText attribute  30
         inside abstract  4
         inside list  17
         inside note  19
         inside section  27
      target attribute
         in eref element  13
         in format element  15
         in reference element  22
         in xref element  35
      texttable element  30
         align attribute  31
         anchor attribute  31
         inside section  27
         style attribute  31
         suppress-title attribute  32
         title attribute  32
      title attribute
         in figure element  14
         in note element  20
         in references element  23
         in section element  27
         in texttable element  32
      title element  32
         abbrev attribute  32
         inside front  15
      toc attribute
         in section element  27
      ttcol element  32
         align attribute  33
         inside texttable  31
         width attribute  33
      type attribute
         in artwork element  8
         in format element  15

   U
      updates attribute
         in rfc element  26
      uri element  33
         inside address  5

   V

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      value attribute
         in seriesInfo element  28
      vspace element  33
         blankLines attribute  33
         inside t  30

   W
      width attribute
         in artwork element  8
         in figure element  15
         in ttcol element  33
      workgroup element  34
         inside front  16

   X
      xml:lang attribute
         in rfc element  27
      xml:space attribute
         in artwork element  8
         in spanx element  29
      xref element  34
         format attribute  34
         inside annotation  5
         inside c  10
         inside postamble  21
         inside preamble  21
         inside t  30
         pageno attribute  35
         target attribute  35
      xref formats
         counter  34
         default  35
         none  35
         title  35

   Y
      year attribute
         in date element  12

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Author's Address

   Julian F. Reschke
   greenbytes GmbH
   Hafenweg 16
   Muenster, NW  48155
   Germany

   EMail: julian.reschke@greenbytes.de
   URI:   http://greenbytes.de/tech/webdav/

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