Once you download the extension, simply drag it onto an open FireFox window.
NOTE: If it's downloaded with a .zip extension, simply change/remove the .zip and make sure to give it a .xpi extension.
What is FB-Secure?
FB-Secure is a FireFox extension that provides users a secure Facebook Application Installation process. Whenever you are about to install a Facebook application, FB-Secure will inform you of requested security permissions and also provide you with data to help you make your decision.
With FB-Secure you are able to control what permissions to grant to your Facebook applications.
What is LIISP?
The Laboratory of Information Integration, Security & Privacy at UNC-Charlotte. liisp.uncc.edu.