[Mr.ac]

If it was a failing slave cylinder you'll see the mess.
This is just my guess, the slave casting is not fully cleaned when installed from the factory. Should it affect performance? I don't think so. But you know o rings and what nots are the fail points.

As for the pic, that's normal. that dirt sticking to the grease used for the pivot fork.
If it bothers you that much you can drain it and fill it. It won't take that much or that long.