Peculiar black tube

In several SEVEL based campers and motorhomes I have had, I have opened the plastic side trims each side of the windscreen. Out pops a black rubber tube, about 5mm diameter and 400mm long, with a white moulded rubber thing at one end. I can't see what it is meant to do. It's almost like a water drain tube, but there isn't anywhere inside the plastic on the screen pillar for it to drain. Does anyone know what it is? It doesn't seem to fit anywhere or do anything so I don't put them back.

Rear window washer tubing routes that way on many vehicles. Why you would have it on a van that doesn't have rear washers, I don't know. Perhaps the same A pillars are used on other models.