On ARM it does, as I mentioned in the article (though it isn't directly useful to us, as it's too different from Linux ones).
But yeah, assuming there will be no Intel machines in Apple's line-up at some point in the future, I wouldn't be surprised if they drop out of the Forum.
They even use device tree on x86 too (in addition to ACPI/EFI). The plaintext password and user guid is passed in chosen fields for instance when boot.efi unlocks an FDE disk.
