Though usually kept close at hand, one would expect a backpack such as this to get heavy after a while, to get set down to rest or simply to get it out of the way. Whether slung over shoulders or set down, the backpack seems to be just that: a well-used backpack, constructed of leather and canvas or oilcloth.
As it lays on the floor, however, the flap seems to have worked loose. What might be in the backpack? A quick peek couldn't hurt, could it? Well, unless there's a medusa head or something similar tucked away in there.