It used to have a huge assembly hall, the rooms for the endowment where you go from room to room at various stages, meeting room for the apostles, the holy of holies and of course the baptismal font.
Then of course the various changing rooms and mechanical rooms.
At one point it had a small apartment. Lorenzo Snow actually lived there at one point.
I have no idea how the renovations will leave it. I understand theaters will replace the live session rooms.