# General extension points

These extension points enable you to extend DITA-OT. You can add Ant targets or imports; add a Java library to the classpath parameter; add a new transformation type; extend a catalog file; add new diagnostic messages, and more.

ant.import
  Adds an Ant import to the main Ant build file.
dita.conductor.lib.import
  Adds a Java library to the DITA-OT classpath.
dita.conductor.target
  Adds an Ant import to the main Ant build file.
  Attention:
  This extension point is deprecated; use `ant.import` instead.
dita.conductor.target.relative
  Adds an Ant import to the main Ant build file.
  Tip:
  As of DITA-OT 3.0, the `ant.import` extension point can be used instead.
dita.conductor.transtype.check

  Adds a new value to the list of valid transformation types.

  Tip:
  This extension point is still supported for backwards compatibility, but since DITA-OT 2.1, any new customizations should instead use the `<transtype>` element in the Plug-in descriptor file to define a new transformation.
dita.specialization.catalog
  Adds the content of a catalog file to the main DITA-OT catalog file.
  Attention:
  This extension point is deprecated; use `dita.specialization.catalog.relative` instead.
dita.specialization.catalog.relative
  Adds the content of a catalog file to the main DITA-OT catalog file.
dita.transtype.print
  Defines a transformation as a print type.
dita.xsl.messages
  Adds new diagnostic messages to DITA-OT.
org.dita.pdf2.catalog.relative
  Adds the content of a catalog file to the main catalog file for the PDF plug-in.