As you can see, you caught the animals on an off-feeding day.
That is what protects the wiring for a trailer hitch wiring harness. It's not supposed to be hanging down. Push it back up until the metal tabs grab hold of it. The bag you speak of is not from the factory - it would have been from a PO.
Inside of the secret panel you found is where a jeep with a trailer two prep package will have the connections to snap in a trailer hitch wiring assembly. That's also where you should keep your spare power steering pulley, your spare serpentine belt, your A/C bypass pulley, your three ton jack stands, three sets of extra clothes (for when you have to crawl underneath the jeep when you're stranded on the side of the road), instructions on how to disable the alarm system because you will forget, a paperclip to hot wire the A/C compressor...what else am I forgetting?