Yes, and I loved it at first sight--it's the only version of Firefox that feels modern and delivers competitive performance in terms of resource efficiency. I'm backing the project via Patreon and really hope it develops into something even better... though I have to admit that I've mostly switched back to Vivaldi because of its greater customization ability and mobile browser (Zen is desktop only) as well as its built-in adblocker, which even works in iOS, unlike uBlock Origin.