No, it's a renderer-agnostic browser built with Common Lisp from the ground up. It currently uses WebkitGTK as its official renderer but there is Blink support planned for early next year via its Electron port.

Thanks! Ever since I used Emacs for the first time I wished I could have a fully Lisp-based configuration for my whole system, and Guix glues them all in pretty neatly

I love it! I went all in on it about a year ago and haven't looked back ever since

Guix since 2 years now. I use it to provision all my systems and having a unified configuration in Guile is just a joy

I haven't looked too much into it, but its development seems to have somewhat stalled against the most recent Emacs versions? I'm aware of many of Elisp's limitations but honestly it's not too bad if you defer the blocking tasks to your OS/WM/etc. I mostly use it for programming, note-taking, and emails nowadays and I don't notice any hiccups

I love it. It lets me abstract away all my program configurations using a single language (Guile Scheme) which removes a lot of mental overhead and makes maintaining my environment a joy.

The second screenshot is me using Tubo in a Chromium browser, yes, because it works better there. However, the first screenshot shows Emacs and Nyxt side by side.