Apple Open Sources iOS Kernel (opens in new tab)

Not in it's current state. It's just a kernel. It's missing key components of the software stack to even make it terminal-only, let alone a GUI. There have been attempts through the years to create a full OS from the bits of OS X/macOS that Apple drops on opensource.apple.com. They do this by surrounding the kernel with FreeBSD or GNU software land, porting Xorg, and other components. See DarwinBSD, OpenDarwin, and PureDarwin. None of the projects proved sustainable in the long-run. It is possible that could change now though with better access to the code on GitHub. It's also possible we could see better drivers developed for hackintosh.

No, because the bootrom only boots signed software. For an emulator, this could be very interesting; if the bootrom is reproduced and drivers are compatible, it could theoretically work.

This is correct. xnu/Darwin, libDispatch, the Objective-C runtime, and many other components have been on opensource.apple.com for years.

It's been on opensource.apple.com for a decade. This Github repo is just a mirror.

Hey so that was my first reaction, and then I thought better of it -- there's no way something this big could happen and not send ripples through the hacker (not cracker, hacker)/programmer/tech community.