http://steamdb.info/app/8930/#section_depots
At steamdb.info, on the Depot tab for Civ 5, there's a new entry, "Bison," with a status of "Unused."
Also, on the History tab, there's this:
15 days ago Changed Depots
235589/config/oslist: windows
235589/name: Bison
That sure sounds...