You can update either the main DITA-OT XML catalog or the XML catalog that is used by the PDF plug-in. This
    enables DITA-OT to support new specializations and document-type shells.
    About this task
      You can use the dita.specialization.catalog.relative and
          org.dita.pdf2.catalog.relative extension points to update the DITA-OT catalog files.
      Remember: The dita.specialization.catalog extension is deprecated. Use
          dita.specialization.catalog.relative instead.
 
    
    Procedure
- 
        Using the OASIS catalog format, create an XML catalog file that contains only the new values that you want
          to add to a DITA-OT catalog file.
      
- 
        Create a plugin.xml file that contains the following content:
        <plugin id="plugin-id">
  <feature extension="extension-point" file="file"/>
</plugin>
 where:
           
            - plugin-id is the plug-in identifier, for example,
                com.example.catalog.
- extension-point is either dita.specialization.catalog.relative
              or org.dita.pdf2.catalog.relative.
- file is the name of the new catalog file, for example,
                catalog-dita.xml. 
 
- 
        Save the new XML catalog file to your plug-in. Be sure that the local file references are relative to the
          location of the catalog and plug-in.
      
- 
        Use the dita install subcommand to install the plug-in.
        
      
Results
The catalog entries inside of the new catalog file are added to the core DITA-OT catalog file.
    Example
      
      This example assumes that catalog-dita.xml contains an OASIS catalog for any document-type
        shells inside this plug-in. The catalog entries in catalog-dita.xml are relative to the
        catalog itself; when the plug-in is installed, they are added to the core DITA-OT catalog (with the correct
        path).
      <plugin id="com.example.catalog">
  <feature extension="dita.specialization.catalog.relative"
           file="catalog-dita.xml"/>
</plugin>