Binary package “gnome-session” in ubuntu groovy

GNOME Session Manager - GNOME 3 session

 The GNOME Session Manager is in charge of starting the core components
 of the GNOME desktop, and applications that should be launched at
 login time. It also features a way to save and restore currently
 running applications.
 .
 This package contains the required components for the standard GNOME 3
 session, based on the GNOME Shell. It can be started from a display
 manager such as GDM, and requires 3D acceleration to work properly.