These are scripts for greasemonkey, a tiny little addon which allows customized Javascript for certain sites.
##facebook-notification.user.js
Facebook has its own notification system, but unfortunately they aren't using HTML 5 notifications. Which is sad, because then these notifications would land directly on ones desktop! These notification integrate seamlessly into the [Freedesktop Notification System](https://developer.gnome.org/notification-spec/) via an [addon](https://github.com/mkiol/GNotifier).