We created an extension to Firefox, which is installed from our website. But when the user tries to install our extension, he sees a message “Firefox prevented this site from asking you to install software on your computer”. Is it possible to prevent this message? Our extension is signed and is downloaded from https://addons.mozilla.org/
This message cannot be prevented programmatically. It is a security feature of Firefox.
It won’t appear for exceptions defined in about:preferences#security -> Exceptions button.
Please note that add-ons are not allowed to change the exception list programmatically.