Which "on change" hooks `smerge-mode` hooks up to?

[Konstantin Kharlamov <hi-angel@yandex.ru>]

I spent some hours trying to debug a problem with highlight getting stuck and I
figured, might just ask at this point more acknowledgeable people.

Problem I debug is basically, that in certain conditions a conflict marker
highlight gets stuck even after the marker was removed.

I figured that I probably need smerge-mode to rescan the buffer if the buffer
was reverted (that only happens when autorevert is enabled). I presume smerge-
mode already does it because it usually removes highlight upon manually removing
conflict markers. And that logic probably has some bug in it.

So, my question is, what "on change" hooks smerge-mode uses to detect that a
change to the buffer has been made to check whether conflict markers are still
in place? I tried searching for the word "hook" over the smerge-mode.el but
didn't find anything relevant.