How do I remove browser add-ons or extensions?
Most web browsers support useful third party add-ons (example: plugins, extensions) that can add new features and functionality. However, if an add-on or extension is malicious, it may cause you to experience spam, cause your Facebook account to send unwanted messages by itself or allow third parties to view and copy your Facebook information, also known as scraping.
If you think your web browser add-ons may be malicious, you can remove them:Mozilla Firefox
Note: Extensions can request certain permissions when added to your browser, including permission to read or edit data on websites you visit. If a malicious browser extension is granted permission to read or change information while you're logged into Facebook, it can potentially view or change your Facebook information.
Facebook can't control how a browser extension uses its permissions or prevent it from viewing your information if you give it permission to view your information on Facebook, so we recommend only using extensions that don't request these permissions and only using extensions from developers you know and trust.