Carbonite. Carbonite, Carbonite, Carbonite. It's the addon that will not leave my inbox alone! The hugely popular and, just plain huge addon suffered a bit of a rocky period around the beginning of Mists of Pandaria. An update from the developers did not seem to be forthcoming, so a fan named Rythal took it upon himself to create a fan update for the popular multipurpose beast. The developers then reappeared, apparently less than impressed with Rythal's efforts, and launched their own update. Rythal politely bowed out of the official Carbonite threads and forums, and set up shop on his own site, where he continued to post unofficial updates.
Then, a while back in late September/early October, the original developers and owners of Carbonite decided that they really didn't have time to maintain this behemoth of an addon. The discussion began about the possibility of making Carbonite Open Source, meaning that Rythal could officially release his patches, and that he and others could push ahead with modularizing, updating, and generally improving Carbonite.