In addition to the pipes, there are also two hitch receivers bolted to the bumper. Looks like it may have been carrying considerable weight...just a guess
I had a hitch receiver added to the rear of my Jayco to tow my pwc as well (it is perfectly legal in WI). I contacted my dealer and the referred me to a local weld shop who fabricated and welded the receiver for me. The shop foreman mentioned that they add tons of receivers to the rear of rv's and asked what I would be hauling as it made a difference on how they fabricated it. They welded two additional cross beams perpendicular to the frame and then welded the receiver tube to them. The entire assembly is completely gusseted and the weld quality is excellent. This receiver is very stout and I was told that I could use it for a bike rack, cargo rack, or trailer and I wouldn't hesitate to use it for any of the aforementioned purposes. Hope this helps.