How to install the latest ESR?

[toastal]

Currently I'm on version 74 with latest.firefox-esr-bin, but version 91 is the new ESR (I need to downgrade because of the Wayland regressions in 92 where I can't right-click, the UI hangs, and I can't see extension pop-ups).

[nbp]

See https://github.com/mozilla/nixpkgs-mozilla/blob/master/firefox-overlay.nix#L184-L188 , the firefoxVersion function is available at lib.firefoxVersion after importing the overlay.

You could add another overlay, loaded after, which looks like:

final: prev:

{
  my-firefox-esr = prev.lib.firefoxVersion {
    name = "Firefox ESR";
    version = "78.14.0esr"; # or prev.lib.firefox_versions.FIREFOX_ESR_NEXT
    release = true;
  };
}

If you are looking for a different version, you can have a look at https://download.cdn.mozilla.net/pub/firefox/releases/

Does that answer your question?

[toastal]

Sure, but why isn't the latest ESR the value for FIREFOX_ESR? Why is it NEXT? That name seems misleading.

[nbp]

The reason is that ESR versions are used by companies/persons which might need time to migrate between one version to the next. Such as updating internal websites of configuration issues like you were experiencing.

Thus, there is a migration period where Mozilla maintains 2 versions of ESR, such that everybody can have time to migrate without using an unmaintained version of Firefox.