The GFDL (GNU Free Documentation License) is available in XML format at http://www.gnu.org/licenses/fdl.xml. For a version in appendix format suitable for including in your document, you can see get the XML for this document from GitHub at https://raw.githubusercontent.com/tLDP/LDP/master/LDP/guide/docbook/LDP-Author-Guide/fdl-appendix.xml.

TLDP template files for DocBook (XML and SGML) and Linuxdoc SGML are available from the TLDP website at http://www.tldp.org/authors/index.html#resources.