Install Unfriend Checker Opera Extension for Facebook:

Latest version: 19, updated on Tuesday, February 25, 2020

Extension is available for install on official addons.opera.com:
https://addons.opera.com/en/extensions/details/unfriend-checker/

If above link is not available for any reason you can install this extension manually following this steps:

Steps to install this extension:

1. Download and unzip Unfriend Checker Opera Extension archive (Click here to download)
2. Open in address bar opera://extensions
3. Activate Developer mode
4. Click on Load unpacked
5. Load Unfriend Checker Opera Extension folder.