When will they open source something meaningful, like Windows, Office or Edge? Prob don't want you to see the telemetry and government spying source code.
You can see the source code of Windows whenever you like. Pay for a Shared Source Initiative license and Microsoft will show you. Or just look at any of the old leaked versions. In neither case is there anything untoward going on in the codebase. Mostly what you’ll find is just integrated proprietary upstream-vendor source code that Microsoft licensed themselves for use in Windows, but does not have an unlimited right to redistribute in source-code form.