They have this Flash-powered demo of Tesseract for GNOME. It's been extended to not only cover Rhythmbox but also Metacity, Mlview, Muine, Sawfish, and Soup.
Exactly understanding this demo though and what Tesseract is about is a bit of a challenge. It basically shows various facts and bugs and details on bugs by analyzing the revision control history (now Git) along with their BugZilla.
The source code to Tesseract isn't opened up at this point, but it's said it will be at some point. There's much more information on this university project on this page or their technical paper: Tesseract: Interactive Visual Exploration of Socio-Technical Relationships in Software Development.
Tesseract was publicly announced today on the Rhythmbox mailing list by one of the university developers in hopes of gathering feedback.