My impression of configuration in nix is that a lot of configuration that in any other distro would be handled by changing some /etc/file is instead done in a completely separate way by editing some nix file. So that's one user-visible way it differs from what I mentioned of using a patch for the /etc/file.

Some simple example I found just now:

https://unix.stackexchange.com/questions/489509/how-do-i-mod...