They’ve been doing it for years. I don’t remember how we first knew, but I know they’ve been using Swift in kernels for at least some of the other chips like the Secure Enclave or whatever.

I’m not sure exactly which. I assume it’s some of the code and not all. But it’s not new in the abstract.

That said I don’t think I’ve heard of it in the kernel of MacOS on the main processor. That may be new.

Either way this is certainly the most concrete announcement I remember them ever giving on this stuff.