I do js so its rare to see a LOC over a few Ks, largest I've seen was about 15K. I know google and facebook have >100K LOC client side JS projects when compiled, I doubt those are in native JS though.
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)