Apparently it was in the manual, but I'm just learning it now.

Back in the day we would often rent games for a weekend and sometimes we would get stuck at some point. There was one particular game that me and my friends really liked (Maui Mallard) on the genesis, but there was one specific point we didn't know what to do. Every now and then we would rent the game again for a weekend in hopes of figuring it out. The game had basically three buttons IIRC: attack, jump and special. You could also press attack and special at the same time for a different attack. So one day I was playing it and reached the point that we all got stuck, and kept trying to figure out how to jump out of the area I was in (there was a clear exit, but too high up). My brother saw me struggling and mockingly said: "come on, do a super jump" and that made me think: can I do special + jump too? I tried it and then learned that this combination allowed climbing through short gaps (and this was the very first such gap in the game - anywhere else the combination did nothing). I was the neighborhood hero for a while thanks to that.