I'm concerned that the complete rewrite in an entirely different language is not a sound technical decision and instead is a ploy to shed copyright claims from past contributors.
Now, based on comments from this thread, the formerly FLOSS project is somehow granting special access to a corporation that apparently is invested in going way out of their way to push implementations that consume the complete rewrite before the world has access to it.
I for one won't be touching Bun. This doesn't pass the smell test. It feels like a bait-and-switch in progress.