So the calendar is based on mkcal and the sqlite db lives at: There is also a second file there called db.changed which always seems to be zero bytes. I don't know what that is for, but presumably the answer is somewhere in the mkcal code. Possibly it's something used when updating the calendar. I don't know.

Still don't know why I can't recreate my deleted calendar, but I suspect if I blow away this db maybe it will be possible. Hmm. Perhaps I will try later.