ok.

This says it works with Firefox 48.0 or later, it doesn't.
I use Firefox 52.9 ESR on my old Windows XP machine, and the current version updated fine there but doesn't work, there's an extension icon but it doesn't do anything. Version 20.3.10 doesn't seem to work either. The last version which does still seem to still work in Firefox 52.9 is 20.2.501.
Please update your Firefox version requirements as it's misleading people at the moment!
Works great on the current Firefox versions on Windows 10 of course.

Avast me gusta mucho y me siento muy confiado. Lo estoy usando desde hace varios años

I like this add-on, but you should really add an option to add websites on some list that will automatically turn off this add-on. I can't see comments on one site that I am trusting, because of Avast Online Security and it's annoying that I need to turn your add-on by myself just to read comments on that site.

And now I need to add few more things after that update. I hate it. The logo on toolbar is no longer changing what gave me an info if the site I am coming on is safe before. The menu of this add-on is bugged and is not showing up or is hiding behind the elements of the page. It also looks worse. I think that I will look for something else for now.

Works very well! I recommend.