The Vivaldi UI is truly what makes the browser unique. As such, it is our most valuable asset in terms of code.
We don’t publish it under an open-source license and only release obfuscated versions of it.
If a new project based on our code implements features that are fundamentally against our ethics (damaging to human rights or to the environment in some way, for instance)
Even though most of the security-relevant code for Vivaldi browser is in Chromium, there is some security-relevant code in the UI as well.
Vivaldi is closed source. It uses Chromium’s base and adds its closed code on top of it and claims it improves security and performance.
https://vivaldi.com/blog/vivaldi-browser-open-source/
TL;DR another privacy grifter