A set of scripts and config files to add support for a session chooser using xsessions/*.desktop files in the xdm display manager.
The intent of this is to be used in fedora to have a feature full xdm, but it could certainly be used on other platforms. This software is certainly dependent on the X session starting scripts.
See the README in the archive.
To use it on fedora, you can set
DISPLAYMANAGER=xdm_xsessions
in /etc/sysconfig/desktop.