Clip Recovering is an advanced tech in ASB2. It allows a way to recover from the edge when you enter free fall by utilizing your character's side special to clip the stage and stall your momentum.
It is performed by using your side special when your character is directly next to the side wall of the platform. If performed correctly, you should stall in the air. Once stalled, some characters can quickly recover, such as Mario by using his strong up-special which should get you back onto the stage. Others characters, such as Sonic, can use clip recovery to dash into the stage itself. From there, an up-special should get you back on the platform.