This describes the Cloud features:
https://www.amazon.com/kindle/connections
There is 200 MB limit to it (why?). But it supports PPT, Google Slides, Google Docs for import in addition to what Send to Kindle supports.
What it exports is unclear. 'documents with annotations' is what?
I've not yet seen anyone do an in-depth walkthrough of this.
I'm curious about where these documents are stored on-device. My assumption is that this storage is not visible over USB (FAQ's explicitly say USB-loaded documents cannot be saved to cloud).
If they plan on rolling features out to older Scribes, what are they waiting for?