is something missing??

Hi! I took this picture with the roof ready for open and the boot lid in the up position. This module lies behind the bulkhead in the boot area, either the drivers side (US etc) or passenger side for those of us who drive on the correct side of the road Lol!!
I would like to know what module this is and why is there a spare port? As we know BMW leave spare nothing so am I missing something??? I know it is a fibre optic link from the connector, so can any help me understand what it is I am looking at??? Many thanks!