plugin.xml

<plugin id="org.dita4publishers.common.html">
  <!-- This plugin provides common XSLT imports and
       supporting code used by all D4P HTML transformation
       type extensions.

       In particular, it centralizes imports of library modules
       so that a given module is imported exactly once.
  -->
  <extension-point id="d4p.common.html.param" behavior="org.dita.dost.platform.InsertAction"/>

  <require plugin="org.dita-community.common.xslt"/>

  <feature extension="package.support.name" value="Eliot Kimber"/>
  <feature extension="package.support.email" value="ekimber@contrext.com"/>
  <feature extension="d4p.common.html.param" value="parameters.xml" type="file" />
  <feature extension="dita.xsl.strings" value="strings/strings.xml" type="file"/>

  <!-- New way of specifying metadata with parameters contributed by the transtype:
        https://github.com/dita-ot/dita-ot/issues/1757
   -->
  <transtype name="d4pCommons" abstract="true" extends="base-html">
    <param name="title.only.topic.class.spec"
      desc="Specifies the @class attribute value to use for title-only topics generated from topicheads."
      type="string">
      <val default="true">- topic/topic </val>
    </param>
    <param name="title.only.topic.title.class.spec"
      desc="Specifies the @class attribute value to use for title-only topics generated from topicheads."
      type="string">
      <val default="true">- topic/topic </val>
    </param>
    <param name="html2.file.organization.strategy"
      desc="Names the output file organization strategy to use for generated files.
      One of the pre-defined strategies or a user-implemented name.
      If the strategy name is not recognized (that is, not handled by the base code or an extension) then the default strategy is applied.
      The default is dependent on the specific transformation type. For HTML2 the default is &quot;as-authored&quot;. For EPUB it is &quot;single-dir&quot;."
      type="string">
      <val>as-authored</val>
      <val>single-dir</val>
    </param>
  </transtype>
</plugin>