Custom PDF plug-ins 
  In most cases, PDF output should be customized by creating custom DITA-OT plug-ins that build on the
    default DITA to PDF transformation. PDF plug-ins can customize covers and page layouts, modify formatting, override
    the logic of the default PDF plug-in, and much more.
  
Types of custom PDF plug-ins PDF plug-in structure Example: Creating a simple PDF plug-in com.example.print-pdf) that creates a new transformation type: print-pdf .Resources for custom PDF plug-ins