iOS 13.1 beta 4, build 17A5844a is now available for registered Apple Developers.
Apparently Apple iOS Team is way too busy to include any notes on iOS Software Update Settings.
Apparently this “No Notes” only appeared on my iPhone XS Max. Full descriptions on iPhone X and iPhone 6s.
It simply says: “iOS 13.1”
On Apple Developer site, it does say iOS 13.1 beta 4.