Uses a male JST-XH 3-pin connector on the bottom to connect to the printer body and a female JST-XH connector on the top to connect the lightbar cable into.

In the center of the plastic part (cf. 2nd pic), the middle pin is soldered through to connect the top and bottom. The other one is connected to a two-stranded cable, interrupting the power and redirecting it to a relay that is controlled by a raspberry pi or similar.