Besides the hidden 'Calendar Quick Compose' feature and new delivery optimization options, Windows 10 build 18912 includes a set of new notification options and a predicative text input feature. As you could expect, they are also hidden.
A few hours ago Microsoft released Windows 10 Build 18912 from the 20H1 branch to Insiders in the Fast Ring. The official announcement highlights only minor changes in this build. However, enthusiasts have discovered a couple of interesting hidden features.
Microsoft is releasing Windows 10 Insider Preview Build 18912 (20H1) to Windows Insiders in the Fast ring. There are no new features. The change log highlights only fixes, and a minor improvement made to Narrator.