It strikes me as a massive anti-pattern to have one developer be the sole contributor of an open-source project sponsored by a $3T company. It doesn't speak well to its longevity or the strength of the sponsorship Microsoft's putting behind it in practice.
There is a difference between a product that a company pushes out as part of its business roadmap with a commercial strategy around it vs. an experimental research project that a single developer takes up on their own initiative.
It is great that they were allowed to open source it.
I hope everyone realizes these comments just discourage companies from letting their employees do their work in the open, in collaboration with the community.
If you want them to wait until everything is super ready (or dead) and then "throw it over the fence" into their public GitHub org, keep it up.