Originally pam.conf was envisioned to be quite simple. Say, about the number of lines in /etc/inetd.conf. It was only later that people started doing these

Originally pam.conf was envisioned to be quite simple. Say, about the number of lines in /etc/inetd.conf. It was only later that people started doing these really complex things, and most of that was because Linux distributions were shipping far more distributed computing components than was originally were envisioned in 1995. Since ordering was critical in PAM config files, and it was presumed that typical sysadmins weren't going to be editing PAM config files, it had to ship with mentions of every single package that might require a PAM config file. And this is what caused it to get super complex --- and not very well documented, since the presumption was that only distro-engineers needed to understand it, and tech writers have always been underappreciated and underpaid for as long as I can remember in the field (and probably longer).