For you, an user that can't wait to explore the latest awesome local files feature, I present a "provisory" solution for file access:
Hubitat File Driver (HFD)
With HFD you can read/write/append to files directly from your apps and drivers, almost like if you were using a File API.
This is a BETA version. Bugs are expected, suggestions are welcome, even complaints too ... part of the business, of course.
I hope it is useful for the community.