I think its those retrofit where they removed the headlight lens/cover to install the projector over the pre-existing assembly (not sure why the previous owner did such a thing though...), then re-baked it to seal things up.
So the plug & play socket at the back is 'closed up'. No clear way to access the bulb except to reverse the process mentioned before.
Not too sure though, just saying what is based on what I found out on my own when trying to replace the bulb and also from bringing it to a few accessory shops.