I am in the midst of the Hircine mission and on my way to Bloated Man Grotto I came across a gated hole in the ground with what I assume is the rotating puzzle to open it. Curious, does anyone know if this is part of a quest or can I just try to open it go in and plunder it? It's off the road to the right when heading west with what looks like a mini Stone Hinge on top of it.

It's just a puzzle with the rewards being a chest and a skill book.