How do I see what happens during NixOS system activation?

It would be practical to have something that shows which commands are executed / files are written/symlinked / … during system activation, to don’t have to look at the activationScripts/… by hand, a simple script that does that, does a bit of formatting, and maybe explains the most common commands is completely ok. (I’m kind of still a NixOS noob, so please be patient with me)