In all probabilities it was not supposed to be a standalone structure. Did it support a fort wall or an overhead superstructure?
One can see a partially buried gateway nearby, unexcavated. This could have been part of a fort wall, an opening to an internal route or some sort of a shelter. Historians should know.
Now for the architects, this picture is amazing:
Arches are seen everywhere in Champaner-Pavagadh structures. However, this is the only structure where I could actually see the details of at least one technique adopted by architects at that point in time, to lock or support stone arches.