Combined dashcam and reversing camera, automatically switches to reverse camera view when you engage reverse.
https://www.ebay.co.uk/itm/4-3-1080P...a/192762019703
Other times you can blank the display for an unobscured, blue-tinted mirror which reduces the need to dip the mirror at night.
Don't mount the rear camera on the tailgate though, the shock of shutting the tailgate will destroy it sooner or later. There's a piece of trim at the rear of the headlining with a centrally mounted turn-button trim buttom, i'm planning on using this on mine to mount the rear camera on.
In case you're wondering, i already have one in my other beast, the old dashcam i had in the 760 has given up the goat - err ghost even!