It's possible to browse the source trees managed on gerrit.wikimedia.org. That is, if you know what you're doing. And you're patient enough to find it. And you have a good memory. And if you're logged in (since you can't seem to browse projects otherwise.
Chad tells me that Ryan has ideas for fixing this up via redirect, so I'm capturing the request to set this up here and in RT:
http://rt.wikimedia.org/Ticket/Display.html?id=2370
Version: unspecified
Severity: enhancement