GNOME Session Manager - GNOME on Xorg 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.
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This package contains the required components for the GNOME on Xorg
session, based on the GNOME Shell. It can be started from a display
manager such as GDM, and requires 3D acceleration to work properly.