I found these extra connectors in the cabinet. What are there? What do they do? Nobody knows. One has black & white wires. One has grey-white and grey-brown.
Update: mystery solved! These are for a bill validator so the game can accept folding money. Thanks to vec-tor at pinside.com!
Update 2: I put the meter on the black & white and got +10.5 VDC, Could come in handy if I ever add additional playfield lighting or other gadgets.