Comment by marcan_42

> I'm assuming that's what raw image is?

You're assuming wrong. Booting unsigned kernels on Apple hardware has been possible since January. This just makes it slightly less annoying since you don't need to build a Mach-O binary to do it, and more future-proof since it decouples it from Apple's binary format which they can change the requirements for at any time (as they did this time). It means I don't have to go off and reverse engineer what the new requirements are, I can just stop using Mach-Os and know the raw option will never break (assuming it continues to exist), since there is nothing to break with a raw file.

Apple's machines are designed as an end-to-end ecosystem that suits their needs, and that they can change at any time - open, but without stability guarantees. This feature is effectively an acknowledgement that people using these machines outside of their ecosystem exist, and might want some stability guarantees.