Firefox stable is pain to install in Debian and in Ubuntu. Let's install self updating binary from directly mozilla.

firefox-ubuntu-debian.md

Download Firefox. https://www.mozilla.org/en-US/firefox

Download the Firefox version you want directly from the official website Uncompress the archives:

• in the /opt directory (system-wide installation - requires Root privileges)
• in your home directory or ~/.opt (install only for the current user)

Create a file firefox-stable.desktop (replace stable with beta or nightly if needed) with the contents below:

• in the /usr/share/applications directory (system-wide installation - requires Root privileges)
• in the ~/.local/share/applications directory (install only for the current user)

[Desktop Entry]
Name=Firefox Stable
Comment=Web Browser
Exec=/opt/firefox/firefox %u
Terminal=false
Type=Application
Icon=/opt/firefox/browser/chrome/icons/default/default128.png
Categories=Network;WebBrowser;
MimeType=text/html;text/xml;application/xhtml+xml;application/xml;application/vnd.mozilla.xul+xml;application/rss+xml;application/rdf+xml;image/gif;image/jpeg;image/png;x-scheme-handler/http;x-scheme-handler/https;
StartupNotify=true
StartupWMClass=firefox
Actions=Private;profile-manager-window;

[Desktop Action Private]
Exec=/opt/firefox/firefox --private-window %u
Name=Open in private mode

[Desktop Action profile-manager-window]
Name=Open the Profile Manager
Exec=/opt/firefox/firefox --ProfileManager

Replace /opt/firefox with the path to the directory where you extracted the archive.

If you want to be able to launch Firefox from a CommandLineInterface, create a symlink to the firefox executable in /usr/local/bin/. For example: sudo ln -s /opt/firefox/firefox /usr/local/bin/firefox

If you want to use your manually installed Firefox as the default DebianAlternatives browser (x-www-browser), run sudo update-alternatives --install /usr/bin/x-www-browser x-www-browser /opt/firefox/firefox 200 && sudo update-alternatives --set x-www-browser /opt/firefox/firefox