[mossTechnician]

Confusingly, that page only provides the changes to the Google Chromium source that allows their UI to run. (I'm not sure it would be easy to discern this without already knowing the source is not fully open.)

https://help.vivaldi.com/desktop/privacy/is-vivaldi-open-sou...

[dismalaf]

https://github.com/ric2b/Vivaldi-browser

Someone mirrored it.