Firefox now has Terms of Use! This'll go over like a lead balloon.
> You give Mozilla all rights necessary to operate Firefox, including processing data as we describe in the Firefox Privacy Notice, as well as acting on your behalf to help you navigate the internet. When you **upload or input information through Firefox, you hereby grant us a nonexclusive, royalty-free, worldwide license to use that information** to help you navigate, experience, and interact with online content as you indicate with your use of Firefox.
https://www.mozilla.org/en-US/about/legal/terms/firefox/
**Update:** See below in the thread for their clarification.
That website actually promotes Firefox, you know. Not sure it fits this thread.
Also from the “European” recommendations, Vivaldi is Chromium, and Mullvad is Tor, which is Firefox.