PHP is well known for having excellent documentation, documentation that is created by volunteers who collectively make changes every day. This HOWTO is designed for people who work on the official PHP documentation. See also » http://www.php.net/docs for viewable and downloadable versions of the PHP manual.
This HOWTO contains information about every aspect of the documentation process, which includes editing the DocBook XML sources, validating changes made to these sources, using the build system to generate documentation into other formats, and general tips like how to use SVN.
Related to this HOWTO is the simple README file that lives within the phpdoc SVN module. It's a quick guide for those already familiar with the basics of XML and SVN.