For help with add-on development, the MDN team has its own forums over here: https://discourse.mozilla.org/c/add-ons As a general comment to get you started: "Could not be verified" usually indicates that the extension is unsigned. You can get the extension signed either through the main Add-ons site submission process or using the command-line web-ext tool. See: https://developer.mozilla.org/Add-ons/Distribution#Signing_your_add-ons