Oh yeah sorry I can see it now, in that case absolutely no idea what it is. As you say didn’t come with the original car.I assuming you've bought the car used? It looks like an aftermarket switch that the previous owner has had fitted to activate something on the car. It could be anything, for example roof lights if it was used in the highway maintenance industry. Definitely isn't a genuine switch that the car came with. Only way to find out is to chase the wiring behind it.
Is there anything which looks aftermarket under the bonnet. I just wonder if its anything to do with a tune. As @gwynp asked what is your model.