How To Install The Latest Firefox (Non-ESR) On Debian 10 Buster (Stable) Or Bullseye (Testing)

Debian Stable and Testing only have Firefox-ESR in their repositories. This article explains how to install the latest Firefox (stable but non-ESR) on Debian Stable (Buster) or Testing (Bullseye).

Firefox ESR, or Extended Support Release, is an official version of Firefox that's focused on security and stability instead of the latest features. During the extended cycle, no new features are added to Firefox ESR, with only high-risk / high-impact security vulnerabilities or major stability issues being fixed.

As such, Firefox ESR is primarily intended at organizations like universities, governments or businesses, as well as individuals who prefer stability to features, and a non-changing user interface between releases.

This article presents 2 3 ways of installing the latest non-ESR Firefox on Debian Stable (Buster) or Testing (Bullseye): from Flatpak / Flathub (available with Firefox 75; this was added to the article in a later edit), installing it from the Debian Unstable repositories (with apt pinning and instructions to revert the changes in case you need it) or manually downloading and including Firefox in the applications menu.

At the time I'm writing this article, the latest Firefox ESR is version 68 (68.2), while the latest regular Firefox release is at version 71.

It's worth noting that the regular Firefox (non-ESR) will use a new, separate profile. Your Firefox-ESR profile will remain on your system, and it will be loaded if you run Firefox ESR, but it won't be used by the regular Firefox version.