Believe it or not this is a "not so uncommon" installation. Either the installer put them their to.... well I don't know. I tried to come up with an excuse for this install but I have nothing.

Photo eye / safety beams, electric eye or whatever you want to call them do have a proper installation procedure. The ceiling isn't part of that procedure as far as I know. Photo sensors are installed to prevent the vehicle door from closing on a vehicle or worse, a child who happens to be playing in the path of the door when it closes. Even without the sensors the door should reverse when it impacts an object.