This patched Firefox was an important security update, and MX pushed this ahead of some of the other Distros - it's in the Arch repos, but it's not made it to Manjaro testing branch yet. It's also not in Linux Mint, Fedora (not even Rawhide), Debian... in fact, have a look for yourself: https://repology.org/metapackage/firefox/versions.
I'm not a fanboy (not even a fan-granddad
), I use a number of Distros, including rolling releases - but things like this prompt update can go unnoticed in reviews, so I thought that I'd give it some publicity here 
