What's this part of the car?
 

Hello, I've been looking at some pics of my C30 and noticed this "wet" patch on it, not sure if that's normal.
What exactly is that part of the car and what might be the problem if there is any?
I don't remember driving through a puddle and it was a sunny day :\

Hi, for me it looks like some fluid from engine bay leaked in some point and left that mark.

Looks like it could be the return pipe in the power steering next to the steering rack. They rust and leak.