There's Adminer, which is some hundreds of kB in a single file...but that's a feature of the build: after packing eeeeverything into one file, it's supposed to be deployed like that; development happens on many sensible-sized files.

I seriously doubt anyone actually edits files over 10 K lines nowadays, even though a script might pack the result into a much larger one.

(Back When Dinosaurs Reigned The Earth, I've worked on a monolithic script of about 50 K lines, but that was just as convenient as you would imagine)