Earlier quoted context omitted.
I am pretty sure anything from Microsoft on GitHub is intended to be open source eventually. Theres no reason they dont have proprietary projects in their own internal version control systems.
Microsoft had multiple Github Enterprise accounts before the acquisition, owned by multiple teams independently inside of Microsoft. They chose to use these instead of Microsoft's own internal repository (some VSS-based thing I think), which management ordered them to use. More internal Microsoft code was being hosted by Github instead by Microsoft. However, the Microsoft account on Github seems to only be public rep…
VSS hasn't been used in a decade or more.