I found them under /usr/share/man/, then “man1”, “man2”, “man3” etc. based on the category system (which I think is like, libraries, syscalls, exes, something like that)

I intuited /usr/share because almost everything the package manager installs will be under /usr somewhere, and man pages aren’t binaries or libraries, they’re architecture-independent, so they can’t be /usr/bin/ or /usr/lib, they’ll probably be in /usr/share and luckily I saw “man” under there.

Hope that helps! Reading the FHS guide is a good learning experience but nobody should have to do it.