Bonjour ".sit" files are an archive format (still) popular in the Mac community. A free unarchiver for WIN used to be found on the editor's website (http://www.stuffit.com/), and might still be. Too bad the free "Deep Paint" is WIN only though... and hopefully "RoadKill" will pe ported to MacOS once it is out of beta (too bad there are only 24 hours in a day...).