A small cluster of dirt on top of the rim of my window frame and slightly on my wall....?

There is this small cluster of dirt on the edge of my window frame in my room, I was slightly on my wall before, But I poked at it and it fell on the floor, I cleaned it up off the floor, but I just went about my day (this was months ago.) SO I was laying on my bed and I remembered the clump of dirt so I went to see if it was there, but I got on a chair to see, apparently I missed a part (I was paranoid the first time I saw it and only poked it off the wall.) but there was some on the edge of the window frame still. It hasn't like grown back or gotten bigger.

But I'm just curious what could it be from.

It was around the time my father first put in my AC. my room in in the basement, so the window is on the ground, and there was an ant and fruit fly problem in that room before I moved in there.

Could it be from the ants? Or the fruit flies?