The book I'm using to learn selenium is based on firefox version 17.0.1. I know this is an older version but I want to be consistent with the book. I installed this older version of firefox and now need to install a compatible version of firebug. There was a website: https://addons.mozilla.org/en-us/firefox/addon/firebug/versions/?page=2 I found a compatible version of firebug on this website but I need to make sure this is a safe and valid website to download from?