Some dashcams, such as the AZDome M63 Pro, have an additional red connection cable on the rear camera. This red cable can be optionally connected to the power supply of the reversing lights. The image from the rear camera will then automatically appear on the screen with parking lines when you put the car in reverse.
Some extension cables, such as those from AZDome, also have this red cable so that you can easily connect it in longer vehicles. If the rear camera of your dashcam does not have the red cable, your dashcam does not support this parking function and you do not need to connect the red cable from the extension cable. It is best to cut or insulate it.