What is this feature for in a BMW?

[FemmeFemme]

Does anyone know what this thing is for in a BMW?

I can’t work out if it’s in the roof or not, but if it is, is it for coat hangers?

We have these in our Volvo. It's for attaching a cage/barrier for dogs.

Google is suggesting for fitting roof bars

If that’s in the boot it’s for attaching the pull-up dog / luggage guard that’s integrated in the luggage cover roller blind thing. There might be some more behind the front seats, for use when the rear seats are folded down

Anyone else thought she was going to ask about the brake or the indicator lights?

No