Re: the approximate doubling of certificate prices.
This has nothing to do with open source, and nothing to do with preventing someone writing something for their own computer.
There's no suggestion that the OS is going to require signed application-level code. There's nothing to stop you from downloading Visual Studio Community Edition (for free), or an open-source IDE such as Eclipse, writing The World's Best Program, publishing the full source code on GitHub under the GPL and also running it on your own computer.
Biting the hand that feeds IT
