С 04.05.2019 перестало работать. проблема подписи.

UPD 05.05.19: Mozilla team fixed the issue =)

Отличное дополнение, защищающее браузер от мутных сайтов. Пусть атакуют, когда их вирусы попросту не запускаются на моём компьютере.

Лучшее дополнение. Simply the Best!

This addon, which I've been using for years, is forcibly disabled in FF 66.0.3. Uninstalling it and reinstalling does not work either. When I click "+ Add to Firefox", i get an error "Download failed. Please check your connection."

edit: This whole issue is unintended. Mozilla is aware of it and is working on a fix right now. Don't uninstall the addons, they will work again when the issue is fixed.
Mozilla thread: https://discourse.mozilla.org/t/certificate-issue-causing-add-ons-to-be-disabled-or-fail-to-install/39047
Reddit, temporary workaround: https://www.reddit.com/r/firefox/comments/bkhtv8/heres_whats_going_on_with_your_addons_being/

Différencie bien les sites sûrs des sites douteux en terme de confidentialité.