This has gotten some attention, especially about a week ago, but I really hope more people will continue to try it and, if interested, support it. It is Firefox, but heavily modified to please a different audience that prefers a slightly different UI than Firefox. It has some of the appeal of Arc, Vivaldi, and the Sidebery extension.
In my view, it is very promising, and all competition in this space is good. Here it is on Github, also.
Tried it for a few days. It works just like firefox minus one embedded video that crashed after 5 secs but worked in ordinary firefox.
What really surprised me was the speed. Loading youtube on firefox ~0.6 on zen ~0.1 which felt rather nice. I’m still not sure if its worth the hassel to switch.