Works Really Well. Maybe Too Well Puntuado con 2 de 5 estrellas

Installed the extension. It wiped every cookie I had immediately, including ones I wished to keep, upon installation, which didn't allow me to setup the whitelist I didn't need until I installed the extension.Now I can't set up the whitelist because I don't know the site addresses of all of those cookies, including a whole lot of do-not-track cookies.This extension -- which doesn't require a restart -- really needs a permission to begin its work before it starts, which means it needs a persistent setup to initialize it. Or at least a warning about how it will behave upon installation.

Without the surprise, wholesale cookies destruction, my star rating would be much, much higher. Right now, 2 stars will have to do. I'm feel more like 1.5, and the .5 would be me being kind.

Esta valoración es de una versión anterior del complemento (0.3.3). 

Sorry about your bad initial experience. Automatically removing cookies is what this add-on is all about. Could I have described the actual behaviour more clearly so you would not have been surpised? English is not my native language; I'm open to suggestions.
Mozilla will not greenlight add-ons that open a modal message when they are loaded like you propose. Opening the warning in a background tab would make no sense, because the cookies would be long gone after you've read it.