I wonder what will Vivaldi do. They say that their built-in content blocker is "good enough" that you supposedly don't need uBO (I very much disagree) but they also keep MV2 extensions working to this day.
They can only support MV2 extensions as long as Google continues to maintain them.
Their tech stack is heavily JavaScript-focused, as their entire UI is written in JavaScript.
Vivaldi said We will keep Manifest v2 for as long as it’s still available in Chromium.[1] They kept it before now because it was little effort.
[1] https://vivaldi.com/blog/manifest-v3-update-vivaldi-is-futur...