I've been using Linux for almost 20 years, including sed a lot of that time, I'm sure I've heard it before, I must have, but when parent wrote it I was like "aah, that makes sense".

Thirty years for me and several more since I learned what sed does and what it's called and never forgot.

I never forget what it does obviously, I use it at least weekly and most of the time daily. But if you asked me what "sed" stand for I'd probably not recall. I might have attempted to work in "extended" somewhere in a guess, because of ex the editor, but besides that :/