A little hard to see, but at the top of the vertical face, where the bolt goes through for the bell housing, green circle. There's a mounting boss behind it, green X, that makes it hard to get a bolt out with a socket. Bolt comes out too far and the socket stops on the boss. Since it's in the trans tunnel, there's not much room for a regular wrench to make a turn.
I bought a set of Crow feet wrenches just for this bolt.