FilaQuilla (latest download version) runs and works as desired on two of
my Win XP pro laptops with the latest FireFox esr version.

But try to install it on a Win XP pro laptop with the same latest
version of FireFox and it first complains that it s unsigned then tells
you how to get around that in about:config.

Once that is done, it still will not allow it to be installed saying it
is not compatible !!!

But I have it installed on two other laptops with the same filtaquilla
and save version of Firefox running Win XP Pro.

It works as advertised there !!!

Thanks a lot for your crappy Firefox browser.