Not very secret actually, it’s right there in front of you! However, how to glitch your way to it may not be as obvious.

I’ve noticed there’s lots of other awesome Borderlands glitching vids here on Youtube but couldn’t tell if there’s one for this specific area yet (North in The Dahl Headlands, check the map in the beginning of the video)

(P.S. Touching most of the cliffs when outside the actual map is instant death. So when you’re trying to get to the desert make sure to land on the sand. May not be a problem in some places though)