The pam-0.72-20 package contains old documentation.
file://localhost/usr/doc/pam-0.72/html/pam.html shows version DRAFT 0.68.
The package is version DRAFT 0.72. I've check the source rpm. The
"pam-redhat-0.72.tar.gz" that is in it also contains old documentation. A
fresh copy of Linux-PAM-0.72.tar.gz from kernel.org contains newer
documentation (version DRAFT v0.71). So, it seems the package is out of
date. I'm not just picking nits here, I actually noticed this because I was
looking for documentation on pam_unix module, which the older documentation
doesn't contain. Compare:

http://www.kernel.org/pub/linux/libs/pam/Linux-PAM-html/pam.html

file://localhost/usr/doc/pam-0.72/html/pam.html