To install and add-on from a file (downloaded from another browser) under Firefox
, follow the below procedure:
- Open Firefox.
- Click on the Firefox button > Options > General.
- In the "Add-ons" section, click on "Manage Add-ons".
- A new page (Add-on manager) shall open, click on the "Tools for add-ons" button (small gear icon) > Install Add-on from file.
- Browse for the location of your add-on and select the file.
- Clicking on the Open button will initiate the installation process.