MediaWiki extensions allow
MediaWiki to be made more advanced and useful for various purposes. These extensions vary greatly in complexity. The
Wikimedia Foundation operates a
Git server where many extensions are hosted, and a directory of them can be found on the MediaWiki website. Some other sites also are known for development of—or support for—extensions are MediaWiki.org, which maintains an extension matrix; and
Google Code. MediaWiki
code review is itself facilitated through a
Gerrit instance. Since version 1.16 MediaWiki also used the
jQuery library.