The development policy defines how Wikimedia software is developed and maintained. This includes MediaWiki core, the bundled skins and extensions, as well as other skins and extensions that are deployed on Wikimedia Foundation wikis.
All Wikimedia engineering endeavors are guided by the Architecture Principles.
Creation of new external services for adding functionality to MediaWiki should follow the related guidelines.
Changes to MediaWiki core that deprecate or remove aspects of the public PHP interface, must follow the Deprecation policy.
Privileged Gerrit users must follow the Gerrit privilege policy when exercising their +2 rights.