Environment variables for Wayland hackers.
Note to myself:
$MOZ_ENABLE_WAYLAND
Enables Wayland for Mozilla products (notably Firefox) if set to 1. Firefox uses GTK so setting GTK_BACKEND=wayland will force it to run on Wayland regardless of if MOZ_ENABLE_WAYLAND. However, it will default to X on GDK_BACKEND=wayland,x11 unless MOZ_ENABLE_WAYLAND=1 is set.