[Spinnaker]

Since I once was a tool and pattern maker, I tried to think like a German Engineer, and came up with this; the grooves are for installing and adjusting the nozzles. Just a guess.
My car had three of them missing when I got it. I was just going to make some plugs for the holes, since I never use the headlight washers. I once tried the washers to see if they worked, and all it does is make a soapy mess all over the fenders. If I drove in bad weather, they might come in handy, but I never drive the Boxster in that kind of weather so I could care less if they worked at all.