@Thyazide @Tutanota
From Vivaldi concerning it being Chromium based:
“Vivaldi is based on Chromium, which is open-source, and all the
improvements we make to this code are published under the same open-
source license. That’s roughly 95% of the code. The remaining 5%, related to Vivaldi’s UI, remains proprietary to this day, although it is still possible to make sense of the obfuscated code and edit it to mod the browser to your liking (something some of the community members do).
As for the reasons for not going fully open-source at the moment, despite
many of Vivaldi’s employees being proponents and users of open-source
software, the devil is in the details. The UI is what makes Vivaldi a unique
browser, we wouldn’t want our work to be used to create a forked browser
that opposes our ethics, and given our limited resources, we cannot
commit to review submitted patches.
This is what works for our company now, but the discussion is, regardless,
far from settled.”