The Wayland Protocol

Wayland is a display server protocol which was (at the time of writing)
introduced as the default in GNOME. It is said that Wayland will eventually
replace X11 as the default display server on Linux and many distributions
have begun implementation of Wayland. Wayland is a more modern protocol and
has a smaller code base currently. Wayland is still under development, and
there are still applications and behaviours that don’t work as expected, you
may find that some applications have not been updated to work properly in
Wayland and currently the only way these applications will run is using Xorg
instead of Wayland. This includes some legacy system applications and games.

Wayland is enabled by default in the GNOME Desktop. You can choose to run
GNOME in X11 by choosing the Gnome on xorg option in the session chooser on
the login screen. Currently KDE still uses X11 and although there is a
plasma-wayland session available, it is not considered stable or bugfree at
this time.

Determining whether you are using Wayland

One way to determine if you’re running in Wayland, is to check the value of
the variable $WAYLAND_DISPLAY. To do this type:

$ echo $WAYLAND_DISPLAY
wayland-0

If you are not running under Wayland the variable will not contain any
values. You can also use loginctl to show you what type of session is
running:

$ loginctl show-session <YOUR_SESSION_NUMBER> -p Type

To determine your session number, simply typing loginctl should provide
your session details.

There is also a legacy X11 server provided with Wayland for compatibility
purposes. To determine what applications are running in this mode, you can
run the following command:

$ xlsclients

There is also the lg (looking glass) tool in GNOME that will allow you to
determine which protocol a specific window is using. To do this, you run the
application by typing lg in the run dialog or at the command line, select
“Windows” in the upper right corner of the tool, and click on the
application name (or open window) you want to know about. If the window is
running in wayland it will say “MetaWindowWayland” and if it is running in
X11 it will say “MetaWindowX11”.

Additional Resources

To find out more about Wayland, please see the following website:

If you need to determine if an issue you are experiencing is related to
wayland, see the Fedora wiki at the link below: