gnome-shell-extension-gamemode - 8-4 main

GameMode optimises your system for peak performance when running a game.
.
This shell extension will show you whether GameMode is active and for which
windows.
.
If you have the Debian gamemode package installed, you can test this
extension by running: /usr/libexec/gamemode-simulate-game
which should pop up a notification that gamemode is running, and
that it has stopped after 10 seconds.