[May 31st 2007] The 'docs' directory contain various text files that should help you understand the most importants classes in MediaWiki. API documentation is automatically generated and updated daily at: http://svn.wikimedia.org/doc/ You can get a fresh version using 'make doc' or mwdocgen.php in the ../maintenance/ directory. For end user / administrators, most of the documentation is located online at: http://www.mediawiki.org/wiki/Project:Help