If you’re wondering how Simon ‘corecode’ Schubert made a Mercurial version of the DragonFly source code, check his recent post that links to his script.
Incidentally, browsing to http://chlamydia.fs.ei.tum.de/hg/dragonfly-src will give you a list of recent source changes that have been picked up by the Mercurial repo. Even better: it comes as an RSS feed!