Darwin Information Typing Architecture (DITA) Version 1.3 Part 1: Base Edition

Chapter 1: Introduction to DITA 1.3
- 1.1.1: About the DITA specification: Base edition
- 1.1.2: Terminology
- 1.1.3: Normative references
- 1.1.4: Non-normative references
- 1.1.5: Formatting conventions in the XHTML version of the specification
Chapter 2: Architectural Specification: Base edition
- 2.2.1: Introduction to DITA
  - 2.2.1.1: DITA terminology and notation
  - 2.2.1.2: Basic concepts
  - 2.2.1.3: File extensions
  - 2.2.1.4: Producing different deliverables from a single source
- 2.2.2: DITA markup
  - 2.2.2.1: DITA topics
    - 2.2.2.1.1: The topic as the basic unit of information
    - 2.2.2.1.2: The benefits of a topic-based architecture
    - 2.2.2.1.3: Disciplined, topic-oriented writing
    - 2.2.2.1.4: Information typing
    - 2.2.2.1.5: Generic topics
    - 2.2.2.1.6: Topic structure
    - 2.2.2.1.7: Topic content
  - 2.2.2.2: DITA maps
    - 2.2.2.2.1: Definition of DITA maps
    - 2.2.2.2.2: Purpose of DITA maps
    - 2.2.2.2.3: DITA map elements
    - 2.2.2.2.4: DITA map attributes
    - 2.2.2.2.5: Examples of DITA maps
      - 2.2.2.2.5.1: Example: DITA map that references a subordinate map
      - 2.2.2.2.5.2: Example: DITA map with a simple relationship table
      - 2.2.2.2.5.3: Example: How the @collection-type and @linking attributes determine links
      - 2.2.2.2.5.4: Example: How the @cascade attribute functions
  - 2.2.2.3: Subject scheme maps and their usage
    - 2.2.2.3.1: Subject scheme maps
    - 2.2.2.3.2: Defining controlled values for attributes
    - 2.2.2.3.3: Binding controlled values to an attribute
    - 2.2.2.3.4: Processing controlled attribute values
    - 2.2.2.3.5: Extending subject schemes
    - 2.2.2.3.6: Scaling a list of controlled values to define a taxonomy
    - 2.2.2.3.7: Classification maps
    - 2.2.2.3.8: Examples of subject scheme maps
      - 2.2.2.3.8.1: Example: How hierarchies defined in a subject scheme map affect filtering
      - 2.2.2.3.8.2: Example: Extending a subject scheme
      - 2.2.2.3.8.3: Example: Extending a subject scheme upwards
      - 2.2.2.3.8.4: Example: Defining values for @deliveryTarget
  - 2.2.2.4: DITA metadata
    - 2.2.2.4.1: Metadata elements
    - 2.2.2.4.2: Metadata attributes
      - 2.2.2.4.2.1: Conditional processing attributes
      - 2.2.2.4.2.2: Translation and localization attributes
      - 2.2.2.4.2.3: Architectural attributes
    - 2.2.2.4.3: Metadata in maps and topics
    - 2.2.2.4.4: Cascading of metadata attributes in a DITA map
    - 2.2.2.4.5: Reconciling topic and map metadata elements
    - 2.2.2.4.6: Map-to-map cascading behaviors
      - 2.2.2.4.6.1: Cascading of attributes from map to map
      - 2.2.2.4.6.2: Cascading of metadata elements from map to map
      - 2.2.2.4.6.3: Cascading of roles from map to map
    - 2.2.2.4.7: Context hooks and window metadata for user assistance
- 2.2.3: DITA addressing
  - 2.2.3.1: ID attribute
  - 2.2.3.2: DITA linking
  - 2.2.3.3: URI-based (direct) addressing
  - 2.2.3.4: Indirect key-based addressing
    - 2.2.3.4.1: Core concepts for working with keys
    - 2.2.3.4.2: Key scopes
    - 2.2.3.4.3: Using keys for addressing
    - 2.2.3.4.4: Addressing keys across scopes
    - 2.2.3.4.5: Cross-deliverable addressing and linking
    - 2.2.3.4.6: Processing key references
    - 2.2.3.4.7: Processing key references for navigation links and images
    - 2.2.3.4.8: Processing key references on <topicref> elements
    - 2.2.3.4.9: Processing key references to generate text or link text
    - 2.2.3.4.10: Examples of keys
      - 2.2.3.4.10.1: Examples: Key definition
      - 2.2.3.4.10.2: Examples: Key definitions for variable text
      - 2.2.3.4.10.3: Example: Scoped key definitions for variable text
      - 2.2.3.4.10.4: Example: Duplicate key definitions within a single map
      - 2.2.3.4.10.5: Example: Duplicate key definitions across multiple maps
      - 2.2.3.4.10.6: Example: Key definition with key reference
      - 2.2.3.4.10.7: Example: References to scoped keys
      - 2.2.3.4.10.8: Example: Key definitions in nested key scopes
      - 2.2.3.4.10.9: Example: Link redirection
      - 2.2.3.4.10.10: Example: Link modification or removal
      - 2.2.3.4.10.11: Example: Links from <term> or <keyword> elements
      - 2.2.3.4.10.12: Example: conref redirection
      - 2.2.3.4.10.13: Example: Key scopes and omnibus publications
      - 2.2.3.4.10.14: Example: How key scopes affect key precedence
      - 2.2.3.4.10.15: Example: Keys and collaboration
- 2.2.4: DITA processing
  - 2.2.4.1: Navigation
    - 2.2.4.1.1: Table of contents
    - 2.2.4.1.2: Indexes
  - 2.2.4.2: Content reference (conref)
    - 2.2.4.2.1: Conref overview
    - 2.2.4.2.2: Processing conrefs
    - 2.2.4.2.3: Processing attributes when resolving conrefs
    - 2.2.4.2.4: Processing xrefs and conrefs within a conref
  - 2.2.4.3: Conditional processing (profiling)
    - 2.2.4.3.1: Conditional processing values and groups
    - 2.2.4.3.2: Filtering
    - 2.2.4.3.3: Flagging
    - 2.2.4.3.4: Conditional processing to generate multiple deliverable types
    - 2.2.4.3.5: Examples of conditional processing
      - 2.2.4.3.5.1: Example: Setting conditional processing values and groups
      - 2.2.4.3.5.2: Example: Filtering and flagging topic content
  - 2.2.4.4: Branch filtering
    - 2.2.4.4.1: Overview of branch filtering
    - 2.2.4.4.2: Branch filtering: Single condition set for a branch
    - 2.2.4.4.3: Branch filtering: Multiple condition sets for a branch
    - 2.2.4.4.4: Branch filtering: Impact on resource and key names
    - 2.2.4.4.5: Branch filtering: Implications of processing order
    - 2.2.4.4.6: Examples of branch filtering
      - 2.2.4.4.6.1: Example: Single <ditavalref> on a branch
      - 2.2.4.4.6.2: Example: Multiple <ditavalref> elements on a branch
      - 2.2.4.4.6.3: Example: Single <ditavalref> as a child of <map>
      - 2.2.4.4.6.4: Example: Single <ditavalref> in a reference to a map
      - 2.2.4.4.6.5: Example: Multiple <ditavalref> elements as children of <map> in a root map
      - 2.2.4.4.6.6: Example: Multiple <ditavalref> elements in a reference to a map
      - 2.2.4.4.6.7: Example: <ditavalref> within a branch that already uses <ditavalref>
      - 2.2.4.4.6.8: Example: <ditavalref> error conditions
  - 2.2.4.5: Chunking
    - 2.2.4.5.1: Using the @chunk attribute
    - 2.2.4.5.2: Chunking examples
  - 2.2.4.6: Translation and localization
    - 2.2.4.6.1: The @xml:lang attribute
    - 2.2.4.6.2: The @dir attribute
  - 2.2.4.7: Processing documents with different values of the @domains attribute
  - 2.2.4.8: Sorting
- 2.2.5: Configuration, specialization, generalization, and constraints
  - 2.2.5.1: Overview of DITA extension facilities
  - 2.2.5.2: Configuration
    - 2.2.5.2.1: Overview of document-type shells
    - 2.2.5.2.2: Rules for document-type shells
    - 2.2.5.2.3: Equivalence of document-type shells
    - 2.2.5.2.4: Conformance of document-type shells
  - 2.2.5.3: Specialization
    - 2.2.5.3.1: Overview of specialization
    - 2.2.5.3.2: Modularization
    - 2.2.5.3.3: Vocabulary modules
    - 2.2.5.3.4: Specialization rules for element types
    - 2.2.5.3.5: Specialization rules for attributes
    - 2.2.5.3.6: @class attribute rules and syntax
    - 2.2.5.3.7: @domains attribute rules and syntax
    - 2.2.5.3.8: Specializing to include non-DITA content
    - 2.2.5.3.9: Sharing elements across specializations
  - 2.2.5.4: Generalization
    - 2.2.5.4.1: Overview of generalization
    - 2.2.5.4.2: Element generalization
    - 2.2.5.4.3: Processor expectations when generalizing elements
    - 2.2.5.4.4: Attribute generalization
    - 2.2.5.4.5: Generalization with cross-specialization dependencies
  - 2.2.5.5: Constraints
    - 2.2.5.5.1: Overview of constraints
    - 2.2.5.5.2: Constraint rules
    - 2.2.5.5.3: Constraints, processing, and interoperability
    - 2.2.5.5.4: Weak and strong constraints
    - 2.2.5.5.5: Conref compatibility with constraints
    - 2.2.5.5.6: Examples: Constraints
      - 2.2.5.5.6.1: Example: Redefine the content model for the <topic> element
      - 2.2.5.5.6.2: Example: Constrain attributes for the <section> element
      - 2.2.5.5.6.3: Example: Constrain a domain module
      - 2.2.5.5.6.4: Example: Replace a base element with the domain extensions
      - 2.2.5.5.6.5: Example: Apply multiple constraints to a single document-type shell
- 2.2.6: Coding practices for DITA grammar files
  - 2.2.6.1: Recognized XML-document grammar mechanisms
  - 2.2.6.2: Normative versions of DITA grammar files
  - 2.2.6.3: DTD coding requirements
    - 2.2.6.3.1: DTD: Overview of coding requirements
    - 2.2.6.3.2: DTD: Coding requirements for document-type shells
    - 2.2.6.3.3: DTD: Coding requirements for element type declarations
    - 2.2.6.3.4: DTD: Coding requirements for structural modules
    - 2.2.6.3.5: DTD: Coding requirements for element domain modules
    - 2.2.6.3.6: DTD: Coding requirements for attribute domain modules
    - 2.2.6.3.7: DTD: Coding requirements for constraint modules
  - 2.2.6.4: RELAX NG coding requirements
    - 2.2.6.4.1: RELAX NG: Overview of coding requirements
    - 2.2.6.4.2: RELAX NG: Coding requirements for document-type shells
    - 2.2.6.4.3: RELAX NG: Coding requirements for element type declarations
    - 2.2.6.4.4: RELAX NG: Coding requirements for structural modules
    - 2.2.6.4.5: RELAX NG: Coding requirements for element domain modules
    - 2.2.6.4.6: RELAX NG: Coding requirements for attribute domain modules
    - 2.2.6.4.7: RELAX NG: Coding requirements for constraint modules
  - 2.2.6.5: XML Schema coding requirements
    - 2.2.6.5.1: XML Schema: Overview and limitations of coding requirements
    - 2.2.6.5.2: XML Schema: Coding requirements for document-type shells
    - 2.2.6.5.3: XML Schema: Coding requirements for element type declarations
    - 2.2.6.5.4: XML Schema: Coding requirements for structural modules
    - 2.2.6.5.5: XML Schema: Coding requirements for attribute domain modules
    - 2.2.6.5.6: XML Schema: Coding requirements for constraint modules
Chapter 3: Language Reference: Base edition
- 3.3.1: Base DITA elements, A to Z
- 3.3.2: Topic elements
  - 3.3.2.1: Basic topic elements
    - 3.3.2.1.1: <topic>
    - 3.3.2.1.2: <title>
    - 3.3.2.1.3: <titlealts>
    - 3.3.2.1.4: <searchtitle>
    - 3.3.2.1.5: <navtitle>
    - 3.3.2.1.6: <shortdesc>
    - 3.3.2.1.7: <abstract>
    - 3.3.2.1.8: <body>
    - 3.3.2.1.9: <bodydiv>
    - 3.3.2.1.10: <related-links>
    - 3.3.2.1.11: <dita>
  - 3.3.2.2: Body elements
    - 3.3.2.2.1: <alt>
    - 3.3.2.2.2: <cite>
    - 3.3.2.2.3: <dd>
    - 3.3.2.2.4: <desc>
    - 3.3.2.2.5: <ddhd>
    - 3.3.2.2.6: <div>
    - 3.3.2.2.7: <dl>
    - 3.3.2.2.8: <dlentry>
    - 3.3.2.2.9: <dlhead>
    - 3.3.2.2.10: <dt>
    - 3.3.2.2.11: <draft-comment>
    - 3.3.2.2.12: <dthd>
    - 3.3.2.2.13: <example>
    - 3.3.2.2.14: <fig>
    - 3.3.2.2.15: <figgroup>
    - 3.3.2.2.16: <fn>
    - 3.3.2.2.17: <image>
    - 3.3.2.2.18: <keyword>
    - 3.3.2.2.19: <li>
    - 3.3.2.2.20: <lines>
    - 3.3.2.2.21: <longdescref>
    - 3.3.2.2.22: <longquoteref>
    - 3.3.2.2.23: <lq>
    - 3.3.2.2.24: <note>
    - 3.3.2.2.25: <object>
    - 3.3.2.2.26: <ol>
    - 3.3.2.2.27: <p>
    - 3.3.2.2.28: <param>
    - 3.3.2.2.29: <ph>
    - 3.3.2.2.30: <pre>
    - 3.3.2.2.31: <q>
    - 3.3.2.2.32: <section>
    - 3.3.2.2.33: <sectiondiv>
    - 3.3.2.2.34: <sl>
    - 3.3.2.2.35: <sli>
    - 3.3.2.2.36: <term>
    - 3.3.2.2.37: <text>
    - 3.3.2.2.38: <tm>
    - 3.3.2.2.39: <ul>
    - 3.3.2.2.40: <xref>
  - 3.3.2.3: Table elements
    - 3.3.2.3.1: <table>
    - 3.3.2.3.2: <tgroup>
    - 3.3.2.3.3: <colspec>
    - 3.3.2.3.4: <thead>
    - 3.3.2.3.5: <tbody>
    - 3.3.2.3.6: <row>
    - 3.3.2.3.7: <entry>
    - 3.3.2.3.8: <simpletable>
    - 3.3.2.3.9: <sthead>
    - 3.3.2.3.10: <strow>
    - 3.3.2.3.11: <stentry>
  - 3.3.2.4: Related links elements
    - 3.3.2.4.1: <link>
    - 3.3.2.4.2: <linklist>
    - 3.3.2.4.3: <linkpool>
    - 3.3.2.4.4: <linktext>
    - 3.3.2.4.5: <linkinfo>
- 3.3.3: Map elements
  - 3.3.3.1: Basic map elements
    - 3.3.3.1.1: <map>
    - 3.3.3.1.2: <topicref>
    - 3.3.3.1.3: <topicmeta>
    - 3.3.3.1.4: <anchor>
    - 3.3.3.1.5: <navref>
    - 3.3.3.1.6: <reltable>
    - 3.3.3.1.7: <relrow>
    - 3.3.3.1.8: <relcell>
    - 3.3.3.1.9: <relheader>
    - 3.3.3.1.10: <relcolspec>
    - 3.3.3.1.11: <ux-window>
  - 3.3.3.2: Map group elements
    - 3.3.3.2.1: <anchorref>
    - 3.3.3.2.2: <keydef>
    - 3.3.3.2.3: <mapref>
    - 3.3.3.2.4: <topicgroup>
    - 3.3.3.2.5: <topichead>
    - 3.3.3.2.6: <topicset>
    - 3.3.3.2.7: <topicsetref>
- 3.3.4: Metadata elements
  - 3.3.4.1: Prolog (metadata) elements
    - 3.3.4.1.1: <prolog>
    - 3.3.4.1.2: <audience>
    - 3.3.4.1.3: <author>
    - 3.3.4.1.4: <brand>
    - 3.3.4.1.5: <category>
    - 3.3.4.1.6: <component>
    - 3.3.4.1.7: <copyright>
    - 3.3.4.1.8: <copyrholder>
    - 3.3.4.1.9: <copyryear>
    - 3.3.4.1.10: <created>
    - 3.3.4.1.11: <critdates>
    - 3.3.4.1.12: <featnum>
    - 3.3.4.1.13: <keywords>
    - 3.3.4.1.14: <metadata>
    - 3.3.4.1.15: <othermeta>
    - 3.3.4.1.16: <permissions>
    - 3.3.4.1.17: <platform>
    - 3.3.4.1.18: <prodinfo>
    - 3.3.4.1.19: <prodname>
    - 3.3.4.1.20: <prognum>
    - 3.3.4.1.21: <publisher>
    - 3.3.4.1.22: <resourceid>
    - 3.3.4.1.23: <revised>
    - 3.3.4.1.24: <series>
    - 3.3.4.1.25: <source>
    - 3.3.4.1.26: <vrmlist>
    - 3.3.4.1.27: <vrm>
  - 3.3.4.2: Indexing group elements
    - 3.3.4.2.1: <indexterm>
    - 3.3.4.2.2: <indextermref>
    - 3.3.4.2.3: <index-see>
    - 3.3.4.2.4: <index-see-also>
    - 3.3.4.2.5: <index-sort-as>
  - 3.3.4.3: Delayed conref resolution elements
    - 3.3.4.3.1: <exportanchors>
    - 3.3.4.3.2: <anchorid>
    - 3.3.4.3.3: <anchorkey>
- 3.3.5: Domain elements
  - 3.3.5.1: Hazard statement elements
    - 3.3.5.1.1: <hazardstatement>
    - 3.3.5.1.2: <consequence>
    - 3.3.5.1.3: <hazardsymbol>
    - 3.3.5.1.4: <howtoavoid>
    - 3.3.5.1.5: <messagepanel>
    - 3.3.5.1.6: <typeofhazard>
  - 3.3.5.2: Highlighting elements
    - 3.3.5.2.1: <b>
    - 3.3.5.2.2: <i>
    - 3.3.5.2.3: <sup>
    - 3.3.5.2.4: <sub>
    - 3.3.5.2.5: <tt>
    - 3.3.5.2.6: <u>
    - 3.3.5.2.7: <line-through>
    - 3.3.5.2.8: <overline>
  - 3.3.5.3: Utilities elements
    - 3.3.5.3.1: <area>
    - 3.3.5.3.2: <coords>
    - 3.3.5.3.3: <imagemap>
    - 3.3.5.3.4: <shape>
    - 3.3.5.3.5: <sort-as>
  - 3.3.5.4: DITAVAL reference domain
    - 3.3.5.4.1: <ditavalref>
    - 3.3.5.4.2: <ditavalmeta>
    - 3.3.5.4.3: <dvrResourcePrefix>
    - 3.3.5.4.4: <dvrResourceSuffix>
    - 3.3.5.4.5: <dvrKeyscopePrefix>
    - 3.3.5.4.6: <dvrKeyscopeSuffix>
- 3.3.6: Classification elements
  - 3.3.6.1: Subject scheme elements
    - 3.3.6.1.1: <subjectScheme>
    - 3.3.6.1.2: <schemeref>
    - 3.3.6.1.3: <hasInstance>
    - 3.3.6.1.4: <hasKind>
    - 3.3.6.1.5: <hasNarrower>
    - 3.3.6.1.6: <hasPart>
    - 3.3.6.1.7: <hasRelated>
    - 3.3.6.1.8: <enumerationdef>
    - 3.3.6.1.9: <elementdef>
    - 3.3.6.1.10: <attributedef>
    - 3.3.6.1.11: <defaultSubject>
    - 3.3.6.1.12: <subjectHead>
    - 3.3.6.1.13: <subjectHeadMeta>
    - 3.3.6.1.14: <subjectdef>
    - 3.3.6.1.15: <relatedSubjects>
    - 3.3.6.1.16: <subjectRelTable>
    - 3.3.6.1.17: <subjectRelHeader>
    - 3.3.6.1.18: <subjectRel>
    - 3.3.6.1.19: <subjectRole>
  - 3.3.6.2: Classification domain elements
    - 3.3.6.2.1: <subjectref>
    - 3.3.6.2.2: <topicapply>
    - 3.3.6.2.3: <topicsubject>
    - 3.3.6.2.4: <topicSubjectTable>
    - 3.3.6.2.5: <topicSubjectHeader>
    - 3.3.6.2.6: <topicSubjectRow>
    - 3.3.6.2.7: <topicCell>
    - 3.3.6.2.8: <subjectCell>
- 3.3.7: Specialization elements
  - 3.3.7.1: <boolean>
  - 3.3.7.2: <data>
  - 3.3.7.3: <data-about>
  - 3.3.7.4: <foreign>
  - 3.3.7.5: <index-base>
  - 3.3.7.6: <itemgroup>
  - 3.3.7.7: <no-topic-nesting>
  - 3.3.7.8: <state>
  - 3.3.7.9: <unknown>
- 3.3.8: Legacy conversion elements
  - 3.3.8.1: <required-cleanup>
- 3.3.9: DITAVAL elements
  - 3.3.9.1: <val>
  - 3.3.9.2: <style-conflict>
  - 3.3.9.3: <prop>
  - 3.3.9.4: <revprop>
  - 3.3.9.5: <startflag>
  - 3.3.9.6: <endflag>
  - 3.3.9.7: <alt-text>
- 3.3.10: Attributes
  - 3.3.10.1: Universal attribute group
    - 3.3.10.1.1: ID attribute group
    - 3.3.10.1.2: Metadata attribute group
    - 3.3.10.1.3: Localization attribute group
    - 3.3.10.1.4: Debug attribute group
  - 3.3.10.2: Architectural attribute group
  - 3.3.10.3: Attributes common to many map elements
  - 3.3.10.4: Complex-table attribute group
  - 3.3.10.5: Data element attributes group
  - 3.3.10.6: Date attributes group
  - 3.3.10.7: Display attribute group
  - 3.3.10.8: Link relationship attribute group
  - 3.3.10.9: Other common attributes
  - 3.3.10.10: Simpletable attribute group
  - 3.3.10.11: Specialization attributes group
  - 3.3.10.12: Topicref element attributes group
  - 3.3.10.13: Complex attribute definitions
    - 3.3.10.13.1: The @href attribute
    - 3.3.10.13.2: The @keys attribute
    - 3.3.10.13.3: The @keyref attribute
    - 3.3.10.13.4: The @keyscope attribute
    - 3.3.10.13.5: The @conref attribute
      - 3.3.10.13.5.1: Using the -dita-use-conref-target value
    - 3.3.10.13.6: The @conaction attribute
    - 3.3.10.13.7: The @conrefend attribute
    - 3.3.10.13.8: The @conkeyref attribute
    - 3.3.10.13.9: The @type attribute
    - 3.3.10.13.10: The @format attribute
    - 3.3.10.13.11: The @scope attribute
    - 3.3.10.13.12: The @role and @otherrole attributes
Chapter 4: Conformance
Appendix A: Acknowledgments
Appendix B: Non-normative information
Appendix C: Content models: Base edition
- C.7.1 A elements
- C.7.2 B elements
- C.7.3 C elements
- C.7.4 D elements
- C.7.5 E elements
- C.7.6 F elements
- C.7.7 H elements
- C.7.8 I elements
- C.7.9 K elements
- C.7.10 L elements
- C.7.11 M elements
- C.7.12 N elements
- C.7.13 O elements
- C.7.14 P elements
- C.7.15 Q elements
- C.7.16 R elements
- C.7.17 S elements
- C.7.18 T elements
- C.7.19 U elements
- C.7.20 V elements
- C.7.21 X elements

Table of contents

Processors can generate a table of contents (TOC) based on the hierarchy of the elements in a DITA map. By default, each <topicref> element in a map represents a node in the TOC. These topic references define a navigation tree.

When a map contains a topic reference to a map (often called a map reference), processors should integrate the navigation tree of the referenced map with the navigation tree of the referencing map at the point of reference. In this way, a deliverable can be compiled from multiple DITA maps.

Note

If a <topicref> element that references a map contains child <topicref> elements, the processing behavior regarding the child <topicref> elements is undefined.

The effective navigation title is used for the value of the TOC node. A TOC node is generated for every <topicref> element that references a topic or specifies a navigation title, except in the following cases:

The @processing-role attribute that is specified on the <topicref> element or an ancestor element is set to "resource-only".
Conditional processing is used to filter out the node or an ancestor node.
The @print attribute is specified on the <topicref> element or an ancestor element, and the current processing does not match the value set by the @print attribute. For example, print="printonly" and the output format is XHTML-based, or print="no" and the output format is PDF. (Note that the @print attribute is deprecated in DITA 1.3; it is replaced by the @deliveryTarget attribute.)
There is no information from which a TOC entry can be constructed; there is no referenced resource or navigation title.
The node is a <topicgroup> element, even if it specifies a navigation title.

To suppress a <topicref> element from appearing in the TOC, set the @toc attribute to "no". The value of the @toc attribute cascades to child <topicref> elements, so if @toc is set to "no" on a particular <topicref>, all children of the <topicref> element are also excluded from the TOC. If a child <topicref> overrides the cascading operation by specifying toc="yes", then the node that specifies toc="yes" appears in the TOC (minus the intermediate nodes that set @toc to "no").

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