Install xul-ext-ubufox by entering the following commands in the terminal:
sudo apt update sudo apt install xul-ext-ubufox
Description:
Ubuntu modifications for Firefox
This package currently ships no functionality, but may be used again in the future to display a restart notification after upgrading Firefox.
Homepage: https://launchpad.net/ubufox
Version: 3.4-0ubuntu1.17.10.1
Section: web