There was an issue like this on CodeMirror: can we use that logic?
The code on CodeMirror changed since this PR, can you update the PR to reflect the new changes?

If there aren't specific requests, can you avoid exposing the setter/getter of scrollbarTrackOffset?

I've already had the appropriate code in there to calculate the scroll height, but I've changed it because CMs code seems to be a tiny bit faster.
The reason the getter and setter is exposed is maybe a bit selfish, but my extension Scroll Arrows would make use of them (it's probably the only one that does so, though).

I left some comments.
I guess the temp folder weren't meant to be committed 😄

Since you have an use case I'm fine with the setter/getter.

@marcelgerber @dakaraphi do you know how this will interact with #12442?
I don't see any changes there on ScrollTrackMarkers.js file but I wonder if there could be any problem.

@ficristo @marcelgerber just looking at the changes here I don't see that this would interact with the tick mark optimizations for search in #12442

@ficristo Changed that doc too 👍

@dakaraphi Thank you to have checked.

@marcelgerber I left a small nit, LGTM with or without it.

@ficristo Thanks for reviewing!
Merging.