I'm using the Firefox release version from Ubuntuzilla on Debian Testing running Gnome, which uses Wayland by default now, so I wondered, does Firefox use Wayland by default? The answer is no, but it is fairly easy to enable it and it seems to work well, with a claimed significant improvement in rendering performance.
To enable Wayland mode in Firefox, edit
/usr/share/applications/firefox-mozilla-build.desktop
to
Exec=env MOZ_ENABLE_WAYLAND=1 firefox %u
(This will also work with other builds of Firefox and executable paths. See StackExchange.)
To get the performance increase in rendering, set
gfx.webrender.compositor.force-enabled
to true in about:config. (Arch Wiki)
There is a bug which results in the window icon and title not displaying.
To correct this I had to change the line
StartupWMClass=Firefox
in the desktop file above to
StartupWMClass=firefox
(StartupWMClass must match the executable name exactly.)
I found the solution in this bug report, of which the previous bug is a duplicate, although more descriptive of this issue.
