Install Firefox (22.04)

Ubuntu 22.04 forces Firefox snap, even if you don't want to use it.

First, remove the snap version of Firefox:

sudo snap remove firefox

Add the official Mozilla Team PPA:

sudo add-apt-repository ppa:mozillateam/ppa

To make sure the system always uses the Mozilla Team PPA, you need to set its priority.
Open this file:

Add this text:

Package: firefox*
Pin: release o=LP-PPA-mozillateam
Pin-Priority: 501

Finally, update and install.

apt update
apt install firefox