Excellent extension.
Contrary to a lot of other extensions that disable JavaScript, this extension looks for <noscript>-tags and adds them to the DOM.
Without this looking for <noscript> you have no JavaScript AND no <noscript>-code. Now you have the best of two worlds.
Especially when you're building sites and you have to check if <noscript> works this is an excellent add-on.
Going every time to about:config or the settings in the developer tools is getting really annoying, simply clicking on an icon works far better.