That there is a circuit breaker, possibly for DC but I'm not sure (will say on the label) which will, of course, act as a switch too. Not good I agree leaving the terminals exposed like that but at least a crimp tool has been used (although not the right one) and its cut into the dash quite neatly too, so not total bodgery and probably installed (at least semi) professionally.
As has been said, follow the wires. Could be for just about anything except a winch.