Fandom/en

Wikia or Fandom is a free web hosting service that uses a fork of MediaWiki as its hosting engine and is known for its wide variety of Wikia extensions. See Wikia's website or the Wikipedia article on Wikia to find out more about Wikia in general.

Source Code
Wikia's Git repository can be accessed at github.com/wikia/app. Please note that it is an entirely separate repository from Wikimedia's and is not affiliated with the official repo.

Extensions
Some of Wikia's extensions can be found at Wikimedia's official Git repository and their appropriate extension pages are located at Wikia extensions.

Other extensions are still located in Wikia's own Git repository, in the folder /extensions/wikia/. It is likely that most of the extensions have dependency on Nirvana (found at /includes/wikia/nirvana), the EasyTemplate class (found at /includes/wikia/ folder on Wikia's Git) and/or they might require custom database tables. Some extensions are not compatible with newer versions and may require.

Source code comments are not as common as in the official MediaWiki either.