Genuinely underrated way to understand circuits. When I was younger and dumber I thought his practice was a bit silly, but man, it really is king.

For someone who is not familiar with that person/channel, what is that way to understand circuits?

Big Clive (a Youtuber from Scotland) often reverse-engineers circuits, resulting in him drawong the schematic in purple sign marker, often while commenting on the virtues (or lack thereof) of the design.

I was just starting to think "doesn't Big Clive visit Edinburgh periodically?" and then OP's suggestion scrolled into view. :)

Sounds like a great video idea for him, really.