What's New in "Android O"

Google I/O is almost here, which means the next iteration of the world's most popular mobile operating system, Android O, is here too. But what is new in the first Developer Preview? Right on top is the big overhaul of Settings and Downloads app (now renamed as Files), among other features like the ability to snooze individual notifications and support for custom lockscreen shortcuts, notification badges on home screen (iOS fans rejoice!), adaptive app icons (circle, squircle or whatever), picture in picture mode, improved autofill (now with support for apps), smarter text selection, high quality audio playback via Bluetooth and options to add a dedicated clipboard to the bottom navigation bar (remember this was hidden in Android Nougat?). Now that we know what features to expect, any guesses on what "O" will be?