Got some fluid coming from somewhere. Pretty sure its not the brakes, that fluid level has not changed over the past two weeks. See pic.

 

Rub your fingers on it and if it smells like stinky hypoid gear lube it's the axle seal
Likely will need some new brake shoes.

 

smell test, or rinse with large amount of water, when dry if it was brakefluid it will be gone, if gear oil it will still be there. water will bead up on oil coated surface, water will absorb into brakefluid.

 

brakefluid will destroy paint so if brakefluid, immediatly rinse the fluid off with lots of water. left as it is if brakefluid, it will strip the paint from the backing plate, cause rust.

 

Being wet on the outside of the backing plate my first guess was brake fluid. Pinhole in the line, loose fitting or loose bleeder. Pull that drum regardless to make sure the shoes are not contaminated with brake fluid, or gear oil. I would also check the wheel cylinder. Pry the boot back a little, being careful not to tear it as it keeps dirt out. Should be dry in there.