what's this above the fuel filter?

Been noticing this lately pooling above the fuel filter. Guessing it is leaking from one of the fuel hoses but they are all dry. Any ideas?

First, please post a smaller photo.

second, you have to verify it is fuel, and not washer fluid or something else

if it fuel, it did not get there by itself.

Clean it up...then look again.

It was indeed fuel, there was a microfracture from one of the elbows causing diesel to seep out over time. Replaced the entire fuel filter assembly to fix (they don't sell just the top part). Something to look for if your car hits the quarter million mile mark.