The tool is actually wonderful. I've used it for years. BUT. And it's an enormous BUT. This extension overrides and locks your notification settings (along with other settings) so that you can't change them. Because of that, any website can..
Good But Why http?..
More details about Web Developer
“Web Developer extension is a Web Developer extension adds a toolbar button that is integrated with different web development tools. This is the official port of the Web Developer extension for Firefox.
The most reliable place for assistance is not in the reviews section listed below however, it is at the Web Developer site in the Help section.”