MediaWiki's source code history began in SourceForge's CVS version control system. We started a project there before the names "MediaWiki" or "Wikimedia" were coined; thus the project name was "wikipedia". This project was used to host pre-MediaWiki wiki software (Magnus Manske's "phase 2"), and finally Lee Daniel Crocker's "phase 3" rewrite which came to be known as MediaWiki.
An extended outage of SourceForge's developer CVS service forced our hand to finally go ahead and set up our own source code repository as of April 1, 2006. That new repository used Subversion (Archived 2004-04-01 at the Wayback Machine), which was ever so slightly trendier than CVS but provided a pretty similar interface.
Between April 1, 2006 and May 31, 2007, the repository was hosted on Brion's offsite server (http://www.leuksman.com).
Between May 31, 2007 and October 23, 2010, the repository was hosted on
mayflower, a Wikimedia server in Amsterdam.
On July 26th 2013, that entire Subversion repository went to read-only for all the projects it supported. It was eventually decommissioned completely in June 2015.