Fake ledge jumping
From SmashWiki, the Super Smash Bros. wiki
It allows the player to "slide" in the air, being unaffected by gravity for a few frames and thus being able to return to the stage without the need for a second jump. Like drop cancelling, it can only be done on a ledge that ends diagonally upwards.
To execute this technique, the player must dash towards the ledge and hit the opposite direction on the stick at most 3 frames before going off the ledge.