I haven't changed anything to the extension as such (and won't for now).
Though I'm 100% for the change to .cbw, I don't want to tamper with extensions for now, as long as extension handling is OBUH (one big ugly hack). Actually I wouldn't have done revision 4428 either, since it adds another piece of hardcode... but it's such an obvious dumb mistake which will annoy users every time they encounter it, so it should be "fixed" nevertheless.