Yes, you saw it. It's PAM being added into Slackware 13.37 in order to make Beta and Unstable version of Google Chrome buildable on -Current (and soon Slackware 13.37). It's not the entire PAM, but only the needed library libpam.so.0 which gets included.
Sox is upgraded to 14.3.2 which includes new features and better stability. This one was requested on LQ. PHP was rebuilt with new config parameter --with-sqlite3=shared. Madplay is patched to fix crashes on x86_64 system, gtk2 is now upgraded to gtk2-2.24.4, and compiz is upgraded to 0.8.8.
The last addition on this update is Linux Kernel 2.6.39-rc1 configs are now being added into /testing directory. This config is intended for testing purposes only and it should be used if you really need to build Linux Kernel 2.6.39-rc1 (and future RCs). Suppose you need a stable Kernel, please use the default stock supported by Slackware 13.37, which is 18.104.22.168 (soon to be 22.214.171.124).
OK, 2 more posts to reach 1000th post. I hope 1000th post is about Slackware 13.37 announcement