Comment 4 for bug 1037616

It's a straightforward bug: the package does not behave as described. Here's a suggested fix: replace the following text:

 - Saved session: if you have saved a session, it is located in
   ~/.config/gnome-session/saved-session/. You can enable automatic
   session saving or manually save it in the "Startup Applications"
   configuration applet.

with:

 - Saved session: if you have saved a session, it is located in
   ~/.config/gnome-session/saved-session/. Automatic saving and
   restoring of the session is currently not reliable (see bug #771896),
   and has been disabled in Ubuntu. To enable automatic session saving:

     dconf write /org/gnome/gnome-session/auto-save-session true

   To re-enable automatic session restoring, set the environment
   variable GNOME_SESSION_SAVE somewhere that is
   read by your display manager's Xsession script (for example, in
   ~/.profile for gdm).

(Note: as far as I'm aware manual session saving is no longer available. As you can see, the name "GNOME_SESSION_SAVE" is an unfortunate choice, as it actually controls whether the session is restored, not whether it is saved.)