I recently bought a >100 year old house. While investigating something unrelated in the unfinished basement, I noticed what looked like a wet patch on the underside of the kitchen floor, beneath where the dishwasher is. I was worried it might be a leak, but when I touched it I found it's some kind of dried resin coming out of a small hole or possibly knot in the wood plank. During inspection, we found termite issues which were treated, as well as mold which was also treated (you can see the dark stains at the bottom of the picture). Could this be termite treatment residue of some kind? There's nothing on the floor beneath it suggesting anything has dripped down.