It is now widely known that Ubuntu 22.04 LTS (Jammy Jellyfish) ships Firefox as a snap, but some people (like me) may prefer installing it from .deb packages to retain control over upgrades or to keep extensions working.

Luckily there is still a PPA serving firefox (and thunderbird) debs at https://launchpad.net/~mozillateam/+archive/ubuntu/ppa maintained by the Mozilla Team. (Thank you!)

You can block the Ubuntu archive’s version that just pulls in the snap by pinning it:

$ cat /etc/apt/preferences.d/firefox-no-snap 
Package: firefox*
Pin: release o=Ubuntu*
Pin-Priority: -1

Now you can remove the transitional package and the Firefox snap itself:

sudo apt purge firefox
sudo snap remove firefox
sudo add-apt-repository ppa:mozillateam/ppa
sudo apt update
sudo apt install firefox

Since the package comes from a PPA unattended-upgrades will not upgrade it automatically, unless you enable this origin:

echo 'Unattended-Upgrade::Allowed-Origins:: "LP-PPA-mozillateam:${distro_codename}";' | sudo tee /etc/apt/apt.conf.d/51unattended-upgrades-firefox

Happy browsing!

Update: I have found a few other, similar guides at https://fostips.com/ubuntu-21-10-two-firefox-remove-snap and https://ubuntuhandbook.org/index.php/2022/04/install-firefox-deb-ubuntu-22-04 and I’ve updated the pinning configuration based on them.