> I think I need a lot more info about this migration

Doesn't sound like it's some Fish-style, full migration to Rust of everything. Seems like they are just moving a couple parts over for evaluation, and then, going forward, making it an official project language that folks are free to use. They note that basically every browser already does that, so this isn't a huge shakeup.

This makes sense because GUI wise Rust isn't really here yet (but it's close).