Hello,
I recently helped move the Firefox snap to use core18 and the new gnome-3-28 extension. From my initial manual testing, it seems to work fine. However, there seems to be an issue with review and submission to the snap store.
Please do let me know if I did something wrong.
Kind regards,
Krish
https://github.com/mozilla/gecko-dev/blob/master/taskcluster/docker/firefox-snap/snapcraft.yaml.in