If my picture messed up during resizing - it looks like a jumper wire between the two screws on the hot side of this outlet.
A factory-new duplex receptacle has a copper "fin" connecting the two screws on each side -- breaking this fin off on the hot (brass) side is done when you want a half-switched receptacle outlet, for instance. It appears somebody broke the fin off at one point, then either the same person or a different person had regrets about the broken fin and replaced it with a jumper wire. So, leave the fin on your new receptacle, and all will be well.
It looks like the outlet was used at one time with that factory installed jumper removed. That would allow you to have two circuits serve each outlet on there. This is often done when you have lights that plug in, you would wire a switch to one outlet for the light, and the other one would still be usable for other things.
I don't think it's legal to put a jumper back in there, typically you can only have one wire per screw terminal.@Makyen pointed out that in this case, the jumper is the only wire in the screw terminal, and the actual circuit wire goes into the push in terminal at the back, so that part of my answer does not apply here.