Early GNOME 3.12 development packages
are beginning to make more extensive use of UPower, the Linux power device abstraction layer that's reaching version 1.0
Among other changes for GNOME 3.11.1, GNOME Shell 3.11.1
is now using UPower directly rather than relying upon the GNOME Settings Daemon. Using UPower directly is to gain more device information itself in determining whether to display a status icon, etc.
Mutter (including Mutter Wayland) has been updated
as well for using the new UPower API.
Expect more exciting changes later on in the GNOME 3.12 development cycle, especially as it pertains to GNOME Wayland support. GNOME 3.12.0 will be officially released in March of next year while until then we will see numerous GNOME 3.11 development releases.