This will make mozillateam's repo preferred over default "snapified": $ cat /etc/apt/preferences.d/firefox-ppa-pin-400 Package: \* Pin: release o=LP-

This will make mozillateam's repo preferred over default "snapified": $ cat /etc/apt/preferences.d/firefox-ppa-pin-400 Package: \* Pin: release o=LP-PPA-mozillateam Pin-Priority: 900