This really was a must have for all users of Mozilla, I had been using this add-on several years ago, and it help me to block a lot of trash content like banners, pop-up windows, etc. However, since the last update of the web browser (57), this does not work anymore, blocks everything, and is hard to understand how it works.
I know all the hard work of the developer to keep running this add-on, and I know this is not your fault, but please, make it work again, no pressure. Your app was really good!!!