- Installing a Packaged Extension (XPI)
- Go to the Add-ons Manager by typing about:addons in the address bar or selecting “Add-ons and Themes” from the browser menu.
- Click the gear icon (settings) in the upper-right corner.
- Choose “Install Add-on From File…” and select your XPI file.
- Loading an Unpacked (Development) Extension
For development or testing, you can load your extension temporarily:
- In the address bar, navigate to about:debugging.
- Click on “This Firefox” (or similar; LibreWolf’s interface is almost identical to Firefox’s).
- Click the “Load Temporary Add-on…” button.
- Browse to your extension’s folder and select the manifest.json file.