It could be purpose built for loading a mower or something, but without the benefit of a tilt bed. The extension would decrease the grade, making it easier to drive up the trailer.maybe it is extremely elegant design intended to carry a very heavy tongue box?
Easy fix if the price is right:
1. Cut off bubba extension and safely haul your mower, or 2. Go for big tires and an axle/suspension beef up; then it doesn't matter if the junk you're cutting off is in the wrong location.
Carry-on trailers can be an okay starting platform if your needs lean to lighter weight rather than big strength. A little reinforcing goes a long way for the angle iron wonders.
But the price has to be right - like almost free.
Every time I get something almost free we both walk away thinking we screwed the other guy in the deal and we end up being both right in the end!