A bit off-topic, but frankly, I think trying to use the Windows source code would be a liability for everyone but something like WINE. Just building it would be

A bit off-topic, but frankly, I think trying to use the Windows source code would be a liability for everyone but something like WINE. Just building it would be a trick, last I heard a full build of Windows took an entire day. I'm guessing it wasn't your beefy Dell machine building it, either. I'll bet there are so many pieces and custom tools and forgotten necessary settings on build machines that building it would be a nightmare. And then there is the test suite. I wouldn't trust a custom build of Windows, who knows all the subtle settings here and there that are necessary to get the same result. I think Microsoft could put the Windows source on GitHub tomorrow and the only thing that would happen is that they'd get a lot of bug bounties and an increase in the number of people they could hire who could just step in and start working without having the six-month ramp up in understanding the relevant code base.