Haha, oops! We actually removed that jump down point (for now), but I forgot to take it out from the code! The idea at first was to have a "hidden tutorial" there, where you could jump down to a small platform with a chest, and then jump down again from that platform. We hoped players would feel so aggravated by the inaccessible chest that they'd figure out you could jump down from marked ledges!
However, due to priority issues, we left that only half implemented and so it felt a bit weird. Instead we'll probably going to add small, faded arrows that appear at jump down points as you get close to them!
That sounds cool, I really thought the round things that indicated the jump down spots looked ugly because there was no grass hanging down from them so they look so out of place. Arrows that works kind of like the treasure X mark sounds way better.