I’d never heard of the term ‘pedal ratcheting’ as a mtb skill until recently when I noticed that it’s one of the skills covered in IMBA’s ICP Level 2 course. See it demonstrated at the 1:18 mark of this video by ICP’s Lead Instructor Trainer Shaums March.
Pedal ratcheting turned out to be helpful last week in two instances. The first was when I was attempting to ride this multiple rock/elevated boardwalk skinny in the skills park at the Lebanon Hills MTB Trail system. I was on my 29’er, trying to get through in the opposite direction from normal (more difficult) without a rear wheel hop: