pdfmime.xml

<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">

<?rfc toc='yes' ?>
<?rfc symrefs='yes' ?>
<?rfc sortrefs='no'?>
<?rfc linkmailto='no'?>
<?rfc compact='yes'?>
<?rfc comments='yes'?>
<?rfc inline='yes'?>

<?rfc-ext parse-xml-in-artwork='yes' ?>

<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>

<rfc number="8118" category="info" obsoletes="3778" submissionType="IETF"
     consensus="yes">

  <front>
    <title abbrev="application/pdf">The application/pdf Media
    Type</title>
    <author initials="M." surname="Hardy" fullname="Matthew Hardy">
      <organization>Adobe Systems Incorporated</organization>
      <address>
        <postal>
          <street>345 Park Ave.</street>
          <city>San Jose</city>
          <region>CA</region>
          <code>95110</code>
          <country>United States of America</country>
        </postal>
        <email>mahardy@adobe.com</email>
      </address>
    </author>
    <author initials="L." surname="Masinter" fullname="Larry Masinter">
      <organization>Adobe Systems Incorporated</organization>
      <address>
        <postal>
          <street>345 Park Ave.</street>
          <city>San Jose</city>
          <region>CA</region>
          <code>95110</code>
          <country>United States of America</country>
        </postal>
        <email>masinter@adobe.com</email>
        <uri>http://LarryMasinter.net</uri>
      </address>
    </author>
    <author initials="D." surname="Markovic" fullname="Dejan Markovic">
      <organization>Adobe Systems Incorporated</organization>
      <address>
        <postal>
          <street>345 Park Ave.</street>
          <city>San Jose</city>
          <region>CA</region>
          <code>95110</code>
          <country>United States of America</country>
        </postal>
        <email>dmarkovi@adobe.com</email>
      </address>
    </author>
    <author initials="D." surname="Johnson" fullname="Duff Johnson">
      <organization>PDF Association</organization>
      <address>
        <postal>
          <street>Neue Kantstrasse 14</street>
          <city>Berlin</city>
          <code>14057</code>
          <country>Germany</country>
        </postal>
        <email>duff.johnson@pdfa.org</email>
      </address>
    </author>
    <author initials="M." surname="Bailey" fullname="Martin Bailey">
      <organization>Global Graphics</organization>
      <address>
        <postal>
          <street>2030 Cambourne Business Park</street>
          <city>Cambridge</city>
          <code>CB23 6DW</code>
          <country>United Kingdom</country>
        </postal>
        <email>martin.bailey@globalgraphics.com</email>
        <uri>http://www.globalgraphics.com</uri>
      </address>
    </author>

    <date month="March" year="2017"/>

<!-- [rfced] Please insert any keywords (beyond those that appear in the
title) for use on http://www.rfc-editor.org/search -->
<!-- [lmm] Added some keywords but would like suggestions for more -->

    <keyword>Portable Document Format</keyword>
    <keyword>MIME type</keyword>
    
    <abstract>
      <t>
        The Portable Document Format (PDF) is an ISO standard (ISO
        32000-1:2008) defining a final-form document representation
        language in use for document exchange, including on the
        Internet, since 1993. This document provides an overview of
        the PDF format and updates the media type registration of
        <spanx style="verb">application/pdf</spanx>. It obsoletes
        RFC 3778.
      </t>
    </abstract>
  </front>
  <middle>
    <section title='Introduction'>
      <t>
        This document is intended to provide updated information
        on the registration of the MIME Media Type
        <spanx style="verb">application/pdf</spanx> for documents
        in the PDF (Portable Document Format) syntax.

<!-- [rfced] Sections 1 and 5:  Because we are planning to publish
this document when Normative Reference [ISOPDF2] is also published,
would it be appropriate to change "[ISOPDF]" to "[ISOPDF2]" in
these sentences?  If yes, please note that we will need confirmation
from you that Annex I is the correct citation for [ISOPDF2] as well.

Original:
  This document is intended to provide updated information on the
   registration of the MIME Media Type "application/pdf" for documents
   defined in the PDF [ISOPDF], "Portable Document Format", syntax.
...
 See [ISOPDF] Annex I, "PDF
 Versions and Compatibility". -->

 It obsoletes
        <xref target='RFC3778'/>.
      </t>
      <t>
        PDF was originally envisioned as a way to reliably communicate
        and view printed information electronically across a
        wide variety of machine configurations, operating
        systems, and communication networks.
      </t>

      <t>
        PDF is used to represent "final form" formatted documents.
        PDF pages may include text, images, graphics, and
        multimedia content such as video and audio.  PDF is also
        capable of containing auxiliary structures, including annotations,
        bookmarks, file attachments, hyperlinks, logical structures,
        and metadata.  These features are useful for navigation and
        building collections of related documents, as well as for
        reviewing and commenting on documents.  A rich JavaScript
        model has been defined for interacting with PDF documents.
      </t>

      <!-- [lmm] clarify relation to PS -->
      <t>
        The imaging model for PDF was originally based on the PostScript <xref target="PS"/>
        page description language, used to render complex text, images, and
        graphics in a device&nbhy;independent and
        resolution-independent manner. 
      </t>

      <!-- [lmm] eXtensible not an error -->
      <t>
        PDF supports encryption and digital signatures.  The
        encryption capability is combined with access control
        information to facilitate management of the
        functionality available to the recipient.  PDF supports
        the inclusion of document and object-level metadata through
        the eXtensible Metadata Platform <xref target='XMP'/>.
      </t>
    </section>
    <section title='History'>
      <t>
        PDF is used widely in the Internet community.  The first
        version of PDF, 1.0, was published in 1993 by Adobe Systems
        Incorporated.  Since then, PDF has grown to be a widely used
        format for capturing and exchanging formatted documents
        electronically across the Web, via email and virtually every
        other document-exchange mechanism.  In 2008, PDF 1.7 was
	adopted as an ISO standard (ISO&nbsp;32000-1:2008 <xref target='ISOPDF'/>)
 	using the ISO "Fast-Track" process. That specification
	is technically identical to Adobe
        Portable Document Format version 1.7 <xref target='AdobePDF'/>.


<!-- [rfced] Section 2:  We see that RFC 3778 cites and lists PDF
version 1.5.  Should either or both of these sentences be updated?
Alternatively, is the "referenced by [RFC3778]" phrase necessary?

Original:
 In
 2008, PDF 1.7 was published as an ISO standard [ISOPDF], ISO
 32000-1:2008.  It was adopted using ISO Fast-Track process and is
 technically identical to Adobe Portable Document Format version 1.7
 [AdobePDF] referenced by [RFC3778].

From RFC 3778:
 [4]   Adobe Systems Incorporated, "PDF Reference, Fourth Edition",
       Version 1.5, August 2003, <http://partners.adobe.com/asn/tech/
       pdf/specifications.jsp>. -->

<!-- [lmm] removed the 'referenced by' and tried to clarify -->

      </t>
      <t>
        The ISO TC-171 committee developed a "refresh" of PDF, known
        as ISO&nbsp;32000-2; the version is PDF 2.0 <xref target="ISOPDF2"/>.
      </t>
      <t>
       In addition to ISO 32000-1:2008 and ISO 32000-2, 
       several subset standards have been defined to
       address specific use cases and standardized by the ISO.
       These standards include
       PDF for Archival (PDF/A) <xref target="ISOPDFA"/>,
       PDF for Engineering (PDF/E) <xref target="ISOPDFE"/>,
       PDF for Universal Accessibility (PDF/UA) <xref target="ISOPDFUA"/>,
       PDF for Variable Data and Transactional Printing (PDF/VT)
       <xref target="ISOPDFVT"/>, and
       PDF for Prepress Digital Data Exchange (PDF/X) <xref target="ISOPDFX"/>.
       The subset standards are fully compliant PDF files capable of being
       displayed in a general PDF viewer.
      </t>
    </section>
    <section title='Fragment Identifiers' anchor='fragments'>
      <t>
        Fragment identifiers appear at the end of a URI and provide a way
        to reference an anchor to subordinate content within the target
        of the URI, or additional parameters to the process of opening
        the identified content. The syntax and semantics of fragment
        identifiers are referenced in the media type definition.
      </t>
      <t>
        The specification of fragment identifiers for PDF appeared
        originally in <xref target='RFC3778'/> and is now included in
        ISO 32000-2 <xref target="ISOPDF2"/>. This section is a
        summary of that material.  Any disagreements between
        <xref target="ISOPDF2"/> and this document should be resolved
        in favor of the ISO&nbsp;32000-2 definition.
      </t>
      <t>
        A fragment identifier for PDF has one or more parameters,
        separated by the ampersand (&amp;) or pound (#)
        character. Each parameter consists of the parameter name, "="
        (equal), and the parameter value; lists of values are
        comma-separated, and parameter value strings may be
        URI&nbhy;encoded <xref target='RFC3986'/>.
        Parameters are processed left to right.  
      </t>
      <t>
        Coordinate values (such as &lt;left&gt;, &lt;right&gt;, and
        &lt;width&gt;) are expressed in the default user space
        coordinate system of the document: 1/72 of an inch
        measured down and to the right from the upper&nbsp;left corner
        of the (current) page (<xref target="ISOPDF2"/> 8.3.2.3
        "User&nbsp;Space").
      </t>
      <t>
        The following parameters identify subordinate content
        of a PDF file but also may be used to set the document view
        to make the (start of) the identified content visible:

      <list style="hanging">
        <t hangText="page=&lt;pageNum&gt;"> <vspace />
        Identifies a specified (physical) page; the first page in the document
        has a pageNum value of 1.
        </t>

        <t hangText="nameddest=&lt;name&gt;"> <vspace />
        Identifies a named destination (<xref target="ISOPDF2"/> 12.3.2.4
        "Named destinations").
        </t>

        <t hangText="structelem=&lt;structID&gt;"> <vspace />
        A byte string with URI encoding; identifies the structure element
        with the ID key within a StructElem dictionary of the document.
        </t>

        <t hangText="comment=&lt;commentID&gt;"> <vspace />
        The value of an annotation name, which is defined by the NM key
        in the corresponding annotation dictionary of the
        selected page (<xref target="ISOPDF2"/> 12.5.2
        "Annotation dictionaries").
        </t>

        <t hangText="ef=&lt;name&gt;"> <vspace />
        Identifies the embedded file where the parameter
        string &lt;name&gt; matches a file
        specification dictionary in the EmbeddedFiles name tree.

        If the "ef" parameter is not at the end of the fragment
        identifier, then the rest of the fragment identifier (after
        the ampersand or hash delimiter) is applied to the embedded
        file according to its own media type. This allows
        identification of content within the embedded file
        (which itself might be a PDF file).
        </t>
        <t>NOTE: When attempting to open a PDF file that is not from a
        trusted source, the processor may choose to prompt the user or
        even prevent the file from being opened.
        </t>
      </list>
      </t>
      <t>These parameters operate on the view of
      the PDF document when it is opened:
      <list style="hanging">
        <t hangText="zoom=&lt;scale&gt;,&lt;left&gt;,&lt;top&gt;"><vspace /> 
        &lt;scale&gt; is the percentage to which the document should
        be zoomed, where a value of 100 corresponds to a zoom of 100%.
        &lt;left&gt; and &lt;top&gt; are optional, but both must be
        specified if either is included.
        </t>

        <t hangText="view=&lt;keyword&gt;,&lt;position&gt;"> <vspace />
        The arguments correspond to those found
        in <xref target="ISOPDF2"/>&nbsp;12.3.2.2 "Explicit destinations". 
        &lt;keyword&gt; is one of the keywords defined in
        <xref target="ISOPDF2"/> "Table 149: Destination syntax"
        with appropriate position values.
        </t>
        <t hangText="viewrect=&lt;left&gt;,&lt;top&gt;,&lt;width&gt;,&lt;height&gt;"> <vspace />
            Set the view rectangle.
        </t>
        <t hangText="highlight=&lt;left&gt;,&lt;right&gt;,&lt;top&gt;,&lt;bottom&gt;"> <vspace />
            Highlight the specified rectangle.
        </t>
        <t hangText="search=&lt;wordList&gt;"> <vspace />
            Open the document and search for one or more words, selecting
            the first matching word in the document. &nbsp;&lt;wordList&gt;
            is a string enclosed in quotation marks, where individual words
            are separated by the space character (or %20).
        </t>
        <t hangText="fdf=&lt;URI&gt;"> <vspace />
          This parameter imports data into PDF form fields. The URI is
          either a relative or absolute URI to a Forms Data Format (FDF)
          or XML FDF (XFDF) file. The fdf parameter should be
          specified as the last parameter to a given URI.
        </t>
    </list>
    </t>
    </section>
    
    <section title='Subset Standards'>
      <t>
        Several subsets of PDF have been published as distinct ISO standards:
        <list style="symbols">
          <t>
            PDF/X <xref target='ISOPDFX'/>, initially released in 2001
            as PDF/X-1a, specifies how to use PDF for graphics
            exchange, with the aim to facilitate correct and
            predictable printing by print service providers. The
            standard has gone through multiple revisions over the
            years and has several published parts, the most recently
            released being part&nbsp;8, specifying different levels of
            conformance: PDF/X-1a:2001, PDF/X-3:2002, PDF/X-1a:2003,
            PDF/X-3:2003, PDF/X-4, PDF/X-4p, PDF&wj;/X-5g,
            PDF/X-5pg, and PDF/X-5n.
          </t>
          <t>
            PDF/A <xref target="ISOPDFA"/>, initially released in 2005, specifies how to use
            PDF for long-term preservation (archiving) of electronic
            documents. It prohibits PDF features that are not well
            suited to long-term archiving of documents, including
            JavaScript or executable file launches. Its
            requirements for PDF/A viewers include color management
            guidelines and support for embedded fonts. There are three
            parts of this standard and a total of eight conformance levels:
            PDF/A-1a, PDF/A-1b, PDF/A-2a,
            PDF/A-2b, PDF/A-2u, PDF&wj;/A-3a, PDF/A-3b, and PDF/A-3u.
          </t>
          <t>
            PDF/E, initially released in 2008 as PDF/E-1 <xref
            target='ISOPDFE'/>, specifies how to use PDF in
            engineering workflows, such as manufacturing, construction,
            and geospatial analysis. Future revisions of PDF/E are
            supposed to include support for 3D PDF workflows.
          </t>
          <t>
            PDF/VT, initially released in 2010, specifies how to use
            PDF in variable and transactional printing. It is based on
            PDF/X and places additional restrictions on PDF content
            elements and supporting metadata. It specifies three
            conformance levels: PDF&wj;/VT-1, PDF/VT-2, and PDF/VT-2s <xref
            target='ISOPDFVT'/>.
          </t>
          <t>
            PDF/UA <xref target='ISOPDFUA'/>, initially released in 2012
            as PDF/UA-1, specifies how to create accessible electronic
            documents. It requires the use of ISO 32000's Tagged PDF
            feature and adds many requirements regarding semantic
            correctness in applying logical structures to content in
            PDF documents.
          </t>
        </list>
      </t>
      <t>
        All of these subset standards use the <spanx
        style="verb">application/pdf</spanx> media type.  The subset
        standards are generally not exclusive, so it is possible to
        construct a PDF file that conforms to, for example, both
        PDF/A-2b and PDF/X-4 subset standards.
      </t>
      <t>
        PDF documents claiming conformance to one or more of the
        subset standards use XMP metadata to identify levels of
        conformance. PDF processors should examine document metadata
        streams for such subset standards identifiers and, if
        appropriate, label documents as such when presenting them to
        the user.
      </t>
    </section>
    
    <section anchor='compat' title='PDF Versions'>
      <t>
        The PDF format has gone through several revisions, primarily for
        the addition of features.  PDF features have generally been
        added in a way that older viewers "fail gracefully", because
        they can just ignore features they do not recognize. Even
        so, the older the PDF version produced, the more legacy
        viewers will support that version, but the fewer features will
        be enabled. The <spanx style="verb">application/pdf</spanx>
	media type is used for all versions.
	See <xref target="ISOPDF2"/> Annex I, "PDF Versions
        and Compatibility".
	<!-- [lmm] please verify -->

      </t>
    </section>

    <section anchor='impl' title='PDF Implementations'>
      <t>
        PDF files are experienced through a reader or viewer of PDF files.
        For most of the common platforms in use (iOS, OS X, Windows, Android,
        ChromeOS, Kindle) and for most browsers (Edge, Safari, Chrome,
        Firefox), PDF viewing is built&nbsp;in. In addition, there are
        many PDF viewers available for download and installation. The PDF
        specification was published and freely available since the format
        was introduced in 1993, so hundreds of companies and
        organizations make tools for PDF creation, viewing, and manipulation.
      </t>
    </section>

    <section anchor='security' title='Security Considerations'>
      <t>
        PDF is certainly a complex media type as per Section&nbsp;4.6 of
        <xref target='RFC6838'/>, which sets requirements for security
        analysis of media type registrations. <xref target='RFC3778'/>
        (which this document obsoletes) contained a detailed analysis
        of some of the security issues for PDF implementations known
        at the time. While the analysis isn't necessarily wrong, the threat
        analysis is much too limited, and the mitigations are somewhat
        out of date. There is now extensive literature on security
        threats involving PDF implementations and how to avoid them,
        consistent with broad implementation over decades.  We are not
        registering a new media type but rather are making a primarily
        administrative update.  With those caveats:
      </t>
      <t>
        The PDF file format allows several constructs that may
        compromise security if handled inadequately by PDF
        processors. For example:

        <list style="symbols">
          <t>
            PDF may contain scripts to customize the displaying
            and processing of PDF files. These scripts are
            expressed in a version of JavaScript and are intended
            for execution by the PDF processor.
          </t>
          <t>
            A PDF file may refer to other PDF files for portions of
            content.  PDF processors may be expected to find and use these
            external files when processing the
            document.

<!-- [rfced] Section 7:  Will "in order to display the document" be
clear to readers?  (For example, should it be "in order to properly
display the document"?)

Original (the previous sentence is included for context):
 o  PDF file may refer to other PDF files for portions of content.
    PDF processors are expected to find these external files and load
    them in order to display the document. -->
<!-- [lmm] broaden where security consideration applies -->

          </t>

          <t>
            PDF may act as a container for various files embedded in
            it (for example, as attached files). PDF processors may
            offer functionality to open and display such files or
            store them on the system, such as with the "ef" open
            action. The PDF specification places no
            restrictions on types of files that may be embedded, so
            PDF processors should be extremely careful to prevent
            unwanted execution of attached executables or
            decompression of attached archives that may store
            dangerous files in the host file system.
          </t>
          <t>
            PDF files may contain links to content on the
            Internet. PDF processors may offer functionality to show
            such content upon following the link.
          </t>
      <t>
        The fragment identifier syntax (<xref target='fragments'/>)
        contains directives for opening ("ef") or including
        ("fdf") additional material.
      </t>

        </list>
        PDF interpreters executing any scripts or programs related to
        these constructs must be extremely careful to ensure that
        untrusted software is executed in a protected environment.
      </t>
      <t>
        In addition, the PDF processor itself, as well as its plugins,
        scripts, etc., may be a source of insecurity, by either obvious
        or subtle means.
      </t>
    </section>
    
    <section title='IANA Considerations'>
      <t>
        This document updates the registration
        of <spanx style="verb">application/pdf</spanx>, a media type
        registration previously defined in <xref target="RFC3778"/>,
        using the registration template defined in <xref target='RFC6838'/>:
      </t>
      <t>
        Type name: application
      </t>
      <t>
        Subtype name: pdf
      </t>
      <t>
        Required parameters: none
      </t>
      <t>
        Optional parameter: none
      </t>
      <t>
        Encoding considerations: binary
      </t>
      <t>
        Security considerations: See <xref target='security'/>
        of this document.
      </t>
      <t>
        Interoperability considerations: See <xref
        target='compat'/> of this document.
      </t>
      <t>
        Published specification: ISO&nbsp;32000-2 (PDF 2.0)
        <xref target='ISOPDF2'/> is the most recent.

<!-- [rfced] Section 8:  Please let us know if  "Published specification"
should reflect PDF 2.0 only. 

Original:
 Published specification: ISO 32000-1:2008 (PDF 1.7) [ISOPDF].  ISO
 32000-2 (PDF 2.0) [ISOPDF2] is currently under development.

Perhaps: 
 Published specification: ISO 32000-2 (PDF 2.0) [ISOPDF2]. -->
<!-- [lmm] use PDF 2 spec only -->

      </t>
      <t>
        Applications that use this media type: See <xref
        target='impl'/> of this document.
      </t>
      <t>
        Fragment identifier considerations: See <xref
        target='fragments'/> of this document.
      </t>
      <t>
        Additional information:
      </t>

      <t><list>
      <t>
        Deprecated alias names for this type: none
      </t>
      <t>
        Magic number(s): All PDF files start with the characters
        "%PDF-" followed by the PDF version number, e.g., "%PDF-1.7"
	or "%PDF-2.0". These characters are in US-ASCII encoding.

<!-- [rfced] Section 8:  '%PDF-' is the only single-quoted item
in this document.  Is the distinction needed, or should this item
be double-quoted?  We will ask IANA to update
http://www.iana.org/assignments/media-types/application/pdf as needed.

Additionally, should 'e.g., "%PDF-1.7"' be changed to
'e.g., "%PDF-2.0"'? 

Original:
 Magic number(s): All PDF files start with the characters '%PDF-'
 followed by the PDF version number, e.g., "%PDF-1.7".  These
 characters are in US-ASCII encoding. -->

<!-- [lmm] fixed -->


      </t>
      <t>
        File extension(s): .pdf
      </t>
      <t>
        Macintosh file type code(s): "PDF "

<!-- [rfced] Section 8:  We removed the space between "PDF" and
the closing quote.  Please let us know if the space should be
restored.

Original:
 Macintosh file type code(s): "PDF "

Changed to:
 Macintosh file type code(s): "PDF" -->

<!-- [lmm] space belongs -->

      </t>
    </list></t>

      <t>
        Person &amp; email address to contact for further information:
        Duff&nbsp;Johnson &lt;duff@duff-johnson.com&gt;, Peter Wyatt
        &lt;Peter.wyatt@cisra.canon.com.au&gt;, ISO 32000 Project Leaders.
      </t>
      <t>
        Intended usage: COMMON
      </t>
      <t>
        Restrictions on usage: none
      </t>
      <t>Author: Authors of this document</t>
      <t>
        Change controller: ISO; in particular, ISO 32000 is by
        ISO&nbsp;TC&nbsp;171&wj;/SC&nbsp;02&wj;/WG 08,
        "PDF specification".  Duff Johnson
        &lt;duff@duff-johnson.com&gt; and Peter Wyatt
        &lt;Peter.wyatt@cisra.canon.com.au&gt; are current ISO 32000
        Project Leaders.
      </t>
      
    </section>
  </middle>
  <back>

<!-- [rfced] Would you like the references to be listed in
alphanumeric order? -->

<!-- [rfced] May we delete the annotations in the references section?  In
speaking with the RSE, we don't believe this type of guidance belongs in the
references.   

   [ISOPDF]   ISO, "Document management - Portable document format -
              Part 1: PDF 1.7", ISO 32000-1:2008, 2008.

              Also available free from Adobe.


   [XMP]      ISO, "Extensible metadata platform (XMP) specification -
              Part 1: Data model, serialization and core properties",
              ISO 16684-1, 2012.

              Not available for free, but there are a number of
              descriptive resources, e.g.,
              <http://en.wikipedia.org/wiki/
              Extensible_Metadata_Platform>

--> 
    <references title="Normative References">
      
      <reference anchor="ISOPDF">
        <front>
          <title>Document management -- Portable document format -- Part 1:
            PDF 1.7</title>
          <author>
            <organization>ISO</organization>
          </author>
          <date year="2008"/>
        </front>
        <seriesInfo name="ISO" value="32000-1:2008"/>
        <!-- [lmm] comment out
	     <annotation>Also available free from Adobe.</annotation> 
	-->
      </reference>

      <reference anchor="ISOPDF2">
        <front>
          <title>Document management -- Portable document format -- Part 2:
            PDF 2.0</title>
          <author>
            <organization>ISO</organization>
          </author>
          <date month="March" year="2017"/>
        </front>
        <seriesInfo name="ISO" value="32000-2"/>
      </reference>
      
    </references>

    <references title="Informative References">

      <reference anchor="ISOPDFX">
        <front>
          <title>Graphic technology -- Prepress digital data exchange using
             PDF -- Part 8: Partial exchange of printing data using PDF 1.6
             (PDF/X-5)</title>
              <author>
                  <organization>ISO</organization>
              </author>
              <date year="2008"/>
          </front>
          <seriesInfo name="ISO" value="15930-8:2008"/>
      </reference>

<!-- [rfced] [ISOPDFX]:  https://www.iso.org/standard/42877.html
says that "This standard (ISO 15930-8) has been revised by
ISO 15930-8:2010."  Would you like to update this listing to
show the 2010 version?

Original:
 [ISOPDFX]  ISO, "Graphic technology - Prepress digital data exchange
            using PDF - Part 8: Partial exchange of printing data
            using PDF 1.6 (PDF/X-5)", ISO 15930-8:2008, 2008. -->
<!-- [lmm] the link is more historical, so leave it -->

      <reference anchor="ISOPDFA">
          <front>
              <title>Document management -- Electronic document file format
                for long-term preservation -- Part 3: Use of ISO 32000-1 with
                support for embedded files (PDF/A-3)</title>
              <author>
                  <organization>ISO</organization>
              </author>
              <date year="2012"/>
          </front>
          <seriesInfo name="ISO" value="19005-3:2012"/>
      </reference>
      <reference anchor="ISOPDFE">
          <front>
              <title>Document management -- Engineering document format
                using PDF -- Part 1: Use of PDF 1.6 (PDF/E-1)</title>
              <author>
                  <organization>ISO</organization>
              </author>
              <date year="2008"/>
          </front>
          <seriesInfo name="ISO" value="24517-1:2008"/>
      </reference>
      <reference anchor="ISOPDFVT">
          <front>
              <title>Graphic technology -- Variable data exchange -- Part 2:
                  Using PDF/X-4 and PDF/X-5 (PDF/VT-1 and PDF/VT-2)</title>
              <author>
                  <organization>ISO</organization>
              </author>
              <date year="2010"/>
          </front>
          <seriesInfo name="ISO" value="16612-2:2010"/>
      </reference>
      <reference anchor="ISOPDFUA">
          <front>
              <title>Document management applications -- Electronic document
                file format enhancement for accessibility -- Part 1: Use of ISO
                32000-1 (PDF/UA-1)</title>
              <author>
                  <organization>ISO</organization>
              </author>
              <date year="2014"/>
          </front>
          <seriesInfo name="ISO" value="14289-1:2014"/>
      </reference>
      
      <reference anchor="XMP">
        <front>
          <title>Graphic technology -- Extensible metadata platform (XMP)
            specification -- Part 1: Data model, serialization and core
            properties</title>
          <author>
            <organization>ISO</organization>
          </author>
          <date year="2012"/>
        </front>
        <seriesInfo name="ISO" value="16684-1"/>
	<!-- [lmm] comment out
        <annotation>Not available for free, but there are a
        number of descriptive resources, e.g., 
        <eref
	    target="http://en.wikipedia.org/wiki/Extensible_Metadata_Platform"/>. 
        </annotation>
	-->
	
      </reference>

      <reference anchor="PS" target="https://www.adobe.com/products/postscript/pdfs/PLRM.pdf">
              <front>
                  <title>PostScript Language Reference, third edition</title>
                  <author>
                      <organization>Adobe Systems Incorporated</organization>
                  </author>
                  <date year="1999"/>
              </front>
      </reference>
      
      <reference anchor="AdobePDF" target="http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/pdf_reference_1-7.pdf">
          <front>
              <title>PDF Reference, sixth edition</title>
              <author>
                  <organization>Adobe Systems Incorporated</organization>
              </author>
              <date year="2006"/>
          </front>
      </reference>

      <?rfc include='reference.RFC.6838' ?>
      <?rfc include='reference.RFC.3986' ?>
      <?rfc include='reference.RFC.3778' ?>
    </references>

    <section title='Changes since RFC 3778'>
      <t>
        This specification replaces RFC 3778, which previously
        defined the <spanx style="verb">application/pdf</spanx>
        Media Type. Differences include the following:
        <list style="symbols">
          <t>
            To reflect the transition from a proprietary specification
            by Adobe to an open ISO standard, the Change Controller
            has changed from Adobe to ISO, and references have been updated.
          </t>
          <t>
            The overview of PDF capabilities, the history of PDF, and
            the descriptions of PDF subsets were updated to reflect
            more recent relevant history.
          </t>
          <t>
            The section on fragment identifiers was updated to closely
            reflect the material that has been added to ISO-32000-2.
          </t>
          <t>
            The status of popular PDF implementations was updated.
          </t>
          <t>
            The Security Considerations section was updated to match the
            current understanding of PDF vulnerabilities.
          </t>
          <t>
            The registration template was updated to match RFC 6838.
          </t>
        </list>
      </t>
      </section>
  </back>
</rfc>