While I am pleased that (1) Brave is not just a Chrome clone and (2) Muon is functioning as a lighter alternative to Electron, I don't know how much this represents a separation from Blink engine. That is: whether they're making a really intensive code change. The company CEO is the creator of Javascript so maybe he's confident he can make it happen. Brave probably can't diverge too far from the base code without reinventing a very big wheel.
I would also like to see if these updates in any way address Haller's comments about Brave back in 2016: https://portableapps.com/comment/229066#comment-229066 but another thread noted they have little interest in portability. So probably not.
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On a related note, Brave has already been forked as "Disenter" (intentionally misspelled). I mention this only to say I'd avoid it. I found their license to be unclear and I wasn't impressed by the "comment anywhere" plugin, which I've seen in various forms over the years. Their current website is also real light on details. The problematic group behind it also doesn't appear to be a software company, so it's unlikely they'll really be moving forward with a strong browser effort.