I know the panels circled in yellow are headlight washers and exist on many cars now. However, on several BMWs I have noticed an extra panel, circled in red. It is not symmetric and I have only noticed it to be located more on the passenger side. What is it for?
Red one is likely to be for a pull hitch. If you get stuck you can insert a screw with the hoop on the end and it will allow someone to pull you out with a chain or winch, putting load in the appropriate place (not the bumper). The screw device is probably in your trunk somewhere.
From the owners manual
The red one is a cover for a screw-hole, into which a tow fitting can be attached. A tow fitting is a small ring, welded to a bolt. You screw it into that place in the bumper, allowing a tow truck to attach to the car without having to climb underneath, potentially hooking to a part of the car that can be damaged.
The yellow ones are covers for the headlight washer nozzles. This is usually optional for higher-end cars. If equipped, when the windshield washer nozzles are activated to squirt washer fluid at the windshield, these nozzles also squirt washer fluid at the headlights. In some cars, they are hidden in the bumper when not actually squirting washer fluid.
