Anyone know what this plug is for?

[BHP231]

In the boot/trunk area there is a small white plug. Nothing is plugged in to it, anyone know what it is for?
Also when I open the passenger door I can hear something electrical clicking in the relay/fuse box area. Normal or gremlins?
Picture of the stray plug in the back of the car below.

[dgcantrell]

Probably a power supply connection for some ancient cell-phone equipment that was available back then. I'll have to check the wiring diagram when I get home this evening. This may come in handy it it's an accessory power connection.

[v2rocket_aka944]

I think that's the power sunroof motor plug.