Help, new to me Lance camper has 2 plugs

Right is std Lance (which Id use because it will accept 8ga power and ground) Adding Lance Lance truck side receptacle you could run 8ga power to say an ignition controlled constant duty relay, just a lot better charging.
The screw on plug? Some back up cameras do use but seems rather large. Even if identified what it might have been sold as/for- no telling what PO did. Meter and trace out.