I have gone through https://wikitech.wikimedia.org/view/How_to_deploy_code and updated it to describe the Magical Git Universe. Specifically, there is a lot of documentation surrounding the submodules that we now use for deploying extensions, and surrounding the process and mechanics of extension deployment branches.

Everything in the deployment guide SHOULD be correct, but some things may be wrong, either because I made a mistake or because I documented the way things should work before actually making them work that way in reality. Either way, if something's wrong, poke me or Chad.

Roan