My understanding from a talk at Ignite 2017 is that certain OS functionality (like some Windows Updates) use it, and that it would get more official support later...but nothing I can find yet, so as you say for the developer it's still an undocumented 'experimental' feature. Hopefully this has changed in the latest build, I will have to look more.

https://view.officeapps.live.com/op/embed.aspx?src=https%3A%... slide 31