Web Compatibility Support • Re: Suggestion for a fallback browser

I'm using Waterfox as backup browser.

Once tweaked (about:config settings, some extensions, and some userChrome.css tweaks), I find it acceptable, even if not as nice as PM (ugly GTK3 instead of GTK2, for a start, and not as customizable an UI), and still lacking extensions (Custom Buttons for example, which I use a lot with PM).