What are these wires for or where should they go?

No that's not original

 

After reviewing my 2012 Liftback, which ought to be essentially identical to a 'v' for nearly everything except rear body shape, my vote is that it was from some aftermarket addition, cut off quickly when sold. Remove that yellow-coated lug, and the rest does look just like mine.

 

Probably went to an aftermarket amplifier, trickle charger or trailer towing kit. I would not worry about it.

 

That looks like someone tapped from the positive battery post to power something like an inverter, or something that
they wanted to operate in or near the vehicle. That type of connector is not commonly used in a Prius, to the best of
my knowledge. I would just remove it and forget that it was ever there.