The way you should look at this website (and this repo) is basically that all the things in there are what we use in our day to day (as @Microsoft).
The code in there is not side-project: those things are used *today* across the company (from Office to Windows to Xbox, etc etc).
Our goal by making this website is to make it easy for you all to benefit from our work: @reactnative can be a rough developer environment from time to time, and we are trying to give back to the community by open-sourcing them, hoping they'll help you too 🤗