You can find instructions on how to install Firefox's Extended Support Release (ESR) on Ubuntu Linux 20.04 LTS or 22.04 LTS in a tutorial published by Linux Capable.
How to Install Firefox ESR on Ubuntu 22.04 or 20.04
Learn how to install Firefox ESR on Ubuntu 22.04 or 20.04 by importing the official PPA and having the most up-to-date browser version.
