While replacing my motor mount I found a small rubber hose. It was dangling close to the motor mount, wasn't connected to anything and had already been mangled by the serpentine band a bit.
I think the other end is coming from the frunk, see first photo, it isn't connected there either.
It runs underneath the car together with three other small tubes, see second photo.
For the time being I've secured it with cable ties.
Any one knows what this small rubber hose is for?