<?xml version="1.0" encoding="UTF-8"?>

<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="syndication-feed-metadata"/>
  <text>
    <status value="extensions"/><div xmlns="http://www.w3.org/1999/xhtml"><p class="res-header-id"><b>Generated Narrative: StructureDefinition syndication-feed-metadata</b></p><table border="0" cellpadding="0" cellspacing="0" style="border: 0px #F0F0F0 solid; font-size: 11px; font-family: verdana; vertical-align: top;"><tr style="border: 1px #F0F0F0 solid; font-size: 11px; font-family: verdana; vertical-align: top"><th style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="The logical name of the element">Name</a></th><th style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Information about the use of the element">Flags</a></th><th style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Minimum and Maximum # of times the element can appear in the instance">Card.</a></th><th style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px; width: 100px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Reference to the type of the element">Type</a></th><th style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Additional information about the element">Description &amp; Constraints</a><span style="float: right"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Legend for this format"><img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3goXBCwdPqAP0wAAAldJREFUOMuNk0tIlFEYhp9z/vE2jHkhxXA0zJCMitrUQlq4lnSltEqCFhFG2MJFhIvIFpkEWaTQqjaWZRkp0g26URZkTpbaaOJkDqk10szoODP//7XIMUe0elcfnPd9zsfLOYplGrpRwZaqTtw3K7PtGem7Q6FoidbGgqHVy/HRb669R+56zx7eRV1L31JGxYbBtjKK93cxeqfyQHbehkZbUkK20goELEuIzEd+dHS+qz/Y8PTSif0FnGkbiwcAjHaU1+QWOptFiyCLp/LnKptpqIuXHx6rbR26kJcBX3yLgBfnd7CxwJmflpP2wUg0HIAoUUpZBmKzELGWcN8nAr6Gpu7tLU/CkwAaoKTWRSQyt89Q8w6J+oVQkKnBoblH7V0PPvUOvDYXfopE/SJmALsxnVm6LbkotrUtNowMeIrVrBcBpaMmdS0j9df7abpSuy7HWehwJdt1lhVwi/J58U5beXGAF6c3UXLycw1wdFklArBn87xdh0ZsZtArghBdAA3+OEDVubG4UEzP6x1FOWneHh2VDAHBAt80IbdXDcesNoCvs3E5AFyNSU5nbrDPZpcUEQQTFZiEVx+51fxMhhyJEAgvlriadIJZZksRuwBYMOPBbO3hePVVqgEJhFeUuFLhIPkRP6BQLIBrmMenujm/3g4zc398awIe90Zb5A1vREALqneMcYgP/xVQWlG+Ncu5vgwwlaUNx+3799rfe96u9K0JSDXcOzOTJg4B6IgmXfsygc7/Bvg9g9E58/cDVmGIBOP/zT8Bz1zqWqpbXIsd0O9hajXfL6u4BaOS6SeWAAAAAElFTkSuQmCC" alt="doco" style="background-color: inherit"/></a></span></th></tr><tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white"><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck1.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="icon_element.gif" alt="." style="background-color: white; background-color: inherit" title="Element" class="hierarchy"/> <a href="StructureDefinition-syndication-feed-metadata-definitions.html#syndication-feed-metadata" title="A reduced description of a feed, used inside an entry's
`⟨source⟩` element (Atom RFC 4287 §4.2.11).

When an entry is copied, mirrored, or aggregated from one feed into
another, the receiving feed SHOULD preserve the originating feed's
identity by including a `⟨source⟩` element on the entry. The
`⟨source⟩` element carries enough metadata to recover the
originating feed even if the entry is later detached from any feed
document.

A consumer that re-encounters the same entry `⟨id⟩` in two
different feeds can use `⟨source⟩` to disambiguate origin.">syndication-feed-metadata</a><a name="syndication-feed-metadata"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><span style="opacity: 0.5">0</span><span style="opacity: 0.5">..</span><span style="opacity: 0.5">*</span></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="http://build.fhir.org/types.html#Base">Base</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">Terminology Syndication Feed Metadata<br/><span style="font-weight:bold">Instances of this logical model can be the target of a Reference</span></td></tr>
<tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: #F7F7F7"><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck10.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_vjoin.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="icon_primitive.png" alt="." style="background-color: #F7F7F7; background-color: inherit" title="Primitive Data Type" class="hierarchy"/> <a href="StructureDefinition-syndication-feed-metadata-definitions.html#syndication-feed-metadata.id" title="Atom `⟨id⟩` of the source feed. Conventionally `urn:uuid:{uuid}`. Same value as the originating feed's `⟨id⟩`.">id</a><a name="syndication-feed-metadata.id"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">0..1</td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="http://hl7.org/fhir/R4/datatypes.html#uri">uri</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">source feed permanent identifier</td></tr>
<tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white"><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck10.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_vjoin.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="icon_primitive.png" alt="." style="background-color: white; background-color: inherit" title="Primitive Data Type" class="hierarchy"/> <a href="StructureDefinition-syndication-feed-metadata-definitions.html#syndication-feed-metadata.title" title="Atom `⟨title⟩` of the source feed.">title</a><a name="syndication-feed-metadata.title"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">0..1</td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="http://hl7.org/fhir/R4/datatypes.html#string">string</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">source feed human-readable name</td></tr>
<tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: #F7F7F7"><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck01.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_vjoin_end.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="icon_datatype.gif" alt="." style="background-color: #F7F7F7; background-color: inherit" title="Data Type" class="hierarchy"/> <a href="StructureDefinition-syndication-feed-metadata-definitions.html#syndication-feed-metadata.link" title="Atom `⟨link⟩` elements from the source feed — typically the source feed's `rel=&quot;self&quot;` link.">link</a><a name="syndication-feed-metadata.link"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">0..*</td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="http://hl7.org/fhir/R4/datatypes.html#BackboneElement">BackboneElement</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">source feed link (typically rel=self)<br/></td></tr>
<tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white"><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck010.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_blank.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_vjoin.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="icon_primitive.png" alt="." style="background-color: white; background-color: inherit" title="Primitive Data Type" class="hierarchy"/> <a href="StructureDefinition-syndication-feed-metadata-definitions.html#syndication-feed-metadata.link.rel" title="link relation">rel</a><a name="syndication-feed-metadata.link.rel"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">0..1</td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="http://hl7.org/fhir/R4/datatypes.html#code">code</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">link relation</td></tr>
<tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: #F7F7F7"><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck010.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_blank.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_vjoin.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="icon_primitive.png" alt="." style="background-color: #F7F7F7; background-color: inherit" title="Primitive Data Type" class="hierarchy"/> <a href="StructureDefinition-syndication-feed-metadata-definitions.html#syndication-feed-metadata.link.type" title="media type">type</a><a name="syndication-feed-metadata.link.type"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">0..1</td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="http://hl7.org/fhir/R4/datatypes.html#code">code</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">media type</td></tr>
<tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white"><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck000.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_blank.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_vjoin_end.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="icon_primitive.png" alt="." style="background-color: white; background-color: inherit" title="Primitive Data Type" class="hierarchy"/> <a href="StructureDefinition-syndication-feed-metadata-definitions.html#syndication-feed-metadata.link.href" title="target URI">href</a><a name="syndication-feed-metadata.link.href"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">1..1</td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="http://hl7.org/fhir/R4/datatypes.html#uri">uri</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">target URI</td></tr>
<tr><td colspan="5" class="hierarchy"><br/><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Legend for this format"><img src="data:image/png;base64,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" alt="doco" style="background-color: inherit"/> Documentation for this format</a></td></tr></table></div>
  </text>
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-type-characteristics">
    <valueCode value="can-be-target"/>
  </extension>
  <url value="https://ontoserver.csiro.au/syndication/StructureDefinition/syndication-feed-metadata"/>
  <version value="0.1.0"/>
  <name value="SyndicationFeedMetadata"/>
  <title value="Terminology Syndication Feed Metadata"/>
  <status value="draft"/>
  <date value="2026-05-09T20:23:33+00:00"/>
  <publisher value="Australian e-Health Research Centre"/>
  <contact>
    <name value="Australian e-Health Research Centre"/>
    <telecom>
      <system value="url"/>
      <value value="https://aehrc.csiro.au"/>
    </telecom>
  </contact>
  <contact>
    <name value="Michael Lawley"/>
    <telecom>
      <system value="email"/>
      <value value="michael.lawley@csiro.au"/>
    </telecom>
  </contact>
  <description value="A reduced description of a feed, used inside an entry's&#xA;`⟨source⟩` element (Atom RFC 4287 §4.2.11).&#xA;&#xA;When an entry is copied, mirrored, or aggregated from one feed into&#xA;another, the receiving feed SHOULD preserve the originating feed's&#xA;identity by including a `⟨source⟩` element on the entry. The&#xA;`⟨source⟩` element carries enough metadata to recover the&#xA;originating feed even if the entry is later detached from any feed&#xA;document.&#xA;&#xA;A consumer that re-encounters the same entry `⟨id⟩` in two&#xA;different feeds can use `⟨source⟩` to disambiguate origin."/>
  <fhirVersion value="4.0.1"/>
  <kind value="logical"/>
  <abstract value="false"/>
  <type value="https://ontoserver.csiro.au/syndication/StructureDefinition/syndication-feed-metadata"/>
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Base"/>
  <derivation value="specialization"/>
  <snapshot>
    <extension url="http://hl7.org/fhir/tools/StructureDefinition/snapshot-base-version">
      <valueString value="4.0.1"/>
    </extension>
    <element id="syndication-feed-metadata">
      <path value="syndication-feed-metadata"/>
      <short value="Terminology Syndication Feed Metadata"/>
      <definition value="A reduced description of a feed, used inside an entry's&#xA;`⟨source⟩` element (Atom RFC 4287 §4.2.11).&#xA;&#xA;When an entry is copied, mirrored, or aggregated from one feed into&#xA;another, the receiving feed SHOULD preserve the originating feed's&#xA;identity by including a `⟨source⟩` element on the entry. The&#xA;`⟨source⟩` element carries enough metadata to recover the&#xA;originating feed even if the entry is later detached from any feed&#xA;document.&#xA;&#xA;A consumer that re-encounters the same entry `⟨id⟩` in two&#xA;different feeds can use `⟨source⟩` to disambiguate origin."/>
      <min value="0"/>
      <max value="*"/>
      <base>
        <path value="Base"/>
        <min value="0"/>
        <max value="*"/>
      </base>
      <isModifier value="false"/>
    </element>
    <element id="syndication-feed-metadata.id">
      <path value="syndication-feed-metadata.id"/>
      <short value="source feed permanent identifier"/>
      <definition value="Atom `⟨id⟩` of the source feed. Conventionally `urn:uuid:{uuid}`. Same value as the originating feed's `⟨id⟩`."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="syndication-feed-metadata.id"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="uri"/>
      </type>
    </element>
    <element id="syndication-feed-metadata.title">
      <path value="syndication-feed-metadata.title"/>
      <short value="source feed human-readable name"/>
      <definition value="Atom `⟨title⟩` of the source feed."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="syndication-feed-metadata.title"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="string"/>
      </type>
    </element>
    <element id="syndication-feed-metadata.link">
      <path value="syndication-feed-metadata.link"/>
      <short value="source feed link (typically rel=self)"/>
      <definition value="Atom `⟨link⟩` elements from the source feed — typically the source feed's `rel=&quot;self&quot;` link."/>
      <min value="0"/>
      <max value="*"/>
      <base>
        <path value="syndication-feed-metadata.link"/>
        <min value="0"/>
        <max value="*"/>
      </base>
      <type>
        <code value="BackboneElement"/>
      </type>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
    </element>
    <element id="syndication-feed-metadata.link.id">
      <path value="syndication-feed-metadata.link.id"/>
      <representation value="xmlAttr"/>
      <short value="Unique id for inter-element referencing"/>
      <definition value="Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Element.id"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="string"/>
        </extension>
        <code value="http://hl7.org/fhirpath/System.String"/>
      </type>
      <isModifier value="false"/>
      <isSummary value="false"/>
      <mapping>
        <identity value="rim"/>
        <map value="n/a"/>
      </mapping>
    </element>
    <element id="syndication-feed-metadata.link.extension">
      <path value="syndication-feed-metadata.link.extension"/>
      <slicing>
        <discriminator>
          <type value="value"/>
          <path value="url"/>
        </discriminator>
        <description value="Extensions are always sliced by (at least) url"/>
        <rules value="open"/>
      </slicing>
      <short value="Additional content defined by implementations"/>
      <definition value="May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension."/>
      <comment value="There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone."/>
      <alias value="extensions"/>
      <alias value="user content"/>
      <min value="0"/>
      <max value="*"/>
      <base>
        <path value="Element.extension"/>
        <min value="0"/>
        <max value="*"/>
      </base>
      <type>
        <code value="Extension"/>
      </type>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <constraint>
        <key value="ext-1"/>
        <severity value="error"/>
        <human value="Must have either extensions or value[x], not both"/>
        <expression value="extension.exists() != value.exists()"/>
        <xpath value="exists(f:extension)!=exists(f:*[starts-with(local-name(.), &quot;value&quot;)])"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Extension"/>
      </constraint>
      <isModifier value="false"/>
      <isSummary value="false"/>
      <mapping>
        <identity value="rim"/>
        <map value="n/a"/>
      </mapping>
    </element>
    <element id="syndication-feed-metadata.link.modifierExtension">
      <path value="syndication-feed-metadata.link.modifierExtension"/>
      <short value="Extensions that cannot be ignored even if unrecognized"/>
      <definition value="May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.&#xA;&#xA;Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself)."/>
      <comment value="There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone."/>
      <requirements value="Modifier extensions allow for extensions that *cannot* be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored.  This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the [definition of modifier extensions](http://hl7.org/fhir/R4/extensibility.html#modifierExtension)."/>
      <alias value="extensions"/>
      <alias value="user content"/>
      <alias value="modifiers"/>
      <min value="0"/>
      <max value="*"/>
      <base>
        <path value="BackboneElement.modifierExtension"/>
        <min value="0"/>
        <max value="*"/>
      </base>
      <type>
        <code value="Extension"/>
      </type>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <constraint>
        <key value="ext-1"/>
        <severity value="error"/>
        <human value="Must have either extensions or value[x], not both"/>
        <expression value="extension.exists() != value.exists()"/>
        <xpath value="exists(f:extension)!=exists(f:*[starts-with(local-name(.), &quot;value&quot;)])"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Extension"/>
      </constraint>
      <isModifier value="true"/>
      <isModifierReason value="Modifier extensions are expected to modify the meaning or interpretation of the element that contains them"/>
      <isSummary value="true"/>
      <mapping>
        <identity value="rim"/>
        <map value="N/A"/>
      </mapping>
    </element>
    <element id="syndication-feed-metadata.link.rel">
      <path value="syndication-feed-metadata.link.rel"/>
      <short value="link relation"/>
      <definition value="link relation"/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="syndication-feed-metadata.link.rel"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="code"/>
      </type>
    </element>
    <element id="syndication-feed-metadata.link.type">
      <path value="syndication-feed-metadata.link.type"/>
      <short value="media type"/>
      <definition value="media type"/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="syndication-feed-metadata.link.type"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="code"/>
      </type>
    </element>
    <element id="syndication-feed-metadata.link.href">
      <path value="syndication-feed-metadata.link.href"/>
      <short value="target URI"/>
      <definition value="target URI"/>
      <min value="1"/>
      <max value="1"/>
      <base>
        <path value="syndication-feed-metadata.link.href"/>
        <min value="1"/>
        <max value="1"/>
      </base>
      <type>
        <code value="uri"/>
      </type>
    </element>
  </snapshot>
  <differential>
    <element id="syndication-feed-metadata">
      <path value="syndication-feed-metadata"/>
      <short value="Terminology Syndication Feed Metadata"/>
      <definition value="A reduced description of a feed, used inside an entry's&#xA;`⟨source⟩` element (Atom RFC 4287 §4.2.11).&#xA;&#xA;When an entry is copied, mirrored, or aggregated from one feed into&#xA;another, the receiving feed SHOULD preserve the originating feed's&#xA;identity by including a `⟨source⟩` element on the entry. The&#xA;`⟨source⟩` element carries enough metadata to recover the&#xA;originating feed even if the entry is later detached from any feed&#xA;document.&#xA;&#xA;A consumer that re-encounters the same entry `⟨id⟩` in two&#xA;different feeds can use `⟨source⟩` to disambiguate origin."/>
    </element>
    <element id="syndication-feed-metadata.id">
      <path value="syndication-feed-metadata.id"/>
      <short value="source feed permanent identifier"/>
      <definition value="Atom `⟨id⟩` of the source feed. Conventionally `urn:uuid:{uuid}`. Same value as the originating feed's `⟨id⟩`."/>
      <min value="0"/>
      <max value="1"/>
      <type>
        <code value="uri"/>
      </type>
    </element>
    <element id="syndication-feed-metadata.title">
      <path value="syndication-feed-metadata.title"/>
      <short value="source feed human-readable name"/>
      <definition value="Atom `⟨title⟩` of the source feed."/>
      <min value="0"/>
      <max value="1"/>
      <type>
        <code value="string"/>
      </type>
    </element>
    <element id="syndication-feed-metadata.link">
      <path value="syndication-feed-metadata.link"/>
      <short value="source feed link (typically rel=self)"/>
      <definition value="Atom `⟨link⟩` elements from the source feed — typically the source feed's `rel=&quot;self&quot;` link."/>
      <min value="0"/>
      <max value="*"/>
      <type>
        <code value="BackboneElement"/>
      </type>
    </element>
    <element id="syndication-feed-metadata.link.rel">
      <path value="syndication-feed-metadata.link.rel"/>
      <short value="link relation"/>
      <definition value="link relation"/>
      <min value="0"/>
      <max value="1"/>
      <type>
        <code value="code"/>
      </type>
    </element>
    <element id="syndication-feed-metadata.link.type">
      <path value="syndication-feed-metadata.link.type"/>
      <short value="media type"/>
      <definition value="media type"/>
      <min value="0"/>
      <max value="1"/>
      <type>
        <code value="code"/>
      </type>
    </element>
    <element id="syndication-feed-metadata.link.href">
      <path value="syndication-feed-metadata.link.href"/>
      <short value="target URI"/>
      <definition value="target URI"/>
      <min value="1"/>
      <max value="1"/>
      <type>
        <code value="uri"/>
      </type>
    </element>
  </differential>
</StructureDefinition>