[LPM1888]

It looks like a hole to me. I wonder if the rover has the capability to look in it?

[Orion78]

I think the rover has a micro-cam which can take highly detailed close up images. I am just making an assumption, but if there is enough light I am sure they could position the rover to see inside it, (assuming it is a hole and not a shadow), with one of the cams. If not with the pancam or the micro-cam, then maybe with one of the nav-cams. I believe they are lower to the ground than the other cameras.