How to install Firefox or other downloadable programs on Ubuntu 18.04
Download from Mozilla Firefox Developer Edition webpage. Extract it with file-roller and move the folder to its final location. A good practice is to install it in /opt/ or /usr/local/.
Once you moved the files to their final location (say /opt/firefox_dev/), you can create the following file ~/.local/share/applications/firefox_dev.desktop to get a launcher with an icon distinct from normal Firefox.
[Desktop Entry] Name=Firefox Developer GenericName=Firefox Developer Edition Exec=/opt/firefox_dev/firefox %u Terminal=false Icon=/opt/firefox_dev/browser/chrome/icons/default/default128.png Type=Application Categories=Application;Network;X-Developer; Comment=Firefox Developer Edition Web Browser. StartupWMClass=Firefox Developer Edition Please note, that the parameter StartupWMClass is added to prevent duplicate icons in the launcher, as explained here.
To mark the launcher as trusted, make it executable:
chmod +x ~/.local/share/applications/firefox_dev.desktop To launch it, navigate to ~/.local/share/applications/ using your “Files” application (ensure you turn on hidden folders), then double-click firefox_dev.desktop. Alternatively, search for Firefox Developer, and simply run the firefox binary, and voilà.
Note that, when you install manually, the F.D.E. does not have the unity global menu by default.