The XSLT import extension points are used to override various steps of XSLT processing. For this, the extension attribute indicates the step that the override applies to; the value attribute is a relative path to the override within the current plugin; if specified, the (optional) type attribute should be set to "file". The plugin installer will add an XSL import statement to the default code so that your override becomes a part of the normal build.
The following XSLT steps are available to override in the core toolkit:
The following two files represent a complete, simple style plug-in. The plugin.xml file declares an XSLT file that extends XHTML processing; the XSLT file overrides default header processing to provide a (theoretical) banner.
plugin.xml:
<?xml version="1.0" encoding="UTF-8"?>
<plugin id="com.example.brandheader">
<feature extension="dita.xsl.xhtml" file="xsl/header.xsl"/>
</plugin>
xsl/header.xsl:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template name="gen-user-header">
<div><img src="http://www.example.com/company_banner.jpg"
alt="Example Company Banner"/></div>
</xsl:template>
</xsl:stylesheet>