At present, the majority of mainstream Linux distributions have transitioned to the Wayland display server as their default option. To confirm whether your system is running on Xorg or Wayland, you can use the following methods for checking.
How to Check whether Wayland or Xorg is in Use
Open the terminal command-line application using the ctrl+alt+t keys and run below command.
echo $XDG_SESSION_TYPE
If you are using Wayland display server, then you will get ‘wayland’ in the output and if you are using Xorg, then you will get ‘X11’ in the output.
Using GNOME shell Restart:
“If you are using the GNOME desktop environment, you can press Alt+F2 together to open the command text box. In the text input box, type ‘r‘ and press Enter.
If you are using Xorg, this action will restart the GNOME shell. However, if you are on Wayland, this method will not work, and you will receive an error message stating ‘Restart is not available on Wayland.‘”