oech3 [1] filed a deletion request for firefox-wayland-mode-hook [2]: MOZ_ENABLE_WAYLAND=1 is easy to set at user's profile. Also `~/.local/share/applications` is usable.
[1] https://aur.archlinux.org/account/oech3/ [2] https://aur.archlinux.org/pkgbase/firefox-wayland-mode-hook/
