It's been more than four years since Google Keep left its Floating Action Button (FAB) behind and switched to a bottom bar with multiple icons for different types of notes. Now Google is trying to bring back the FAB with a slightly revamped design.
With version 5.19.451 of Keep (APK Mirror), some users have noticed a new bottom bar in the app. The four icons for creating a checklist, hand drawing, voice note, or image note are still there, but they've been moved from the right to the left. The text note option used to be triggered by tapping "Take a note...", but that's now been replaced by a FAB button on the right.
The button has Google's four signature colors in a plus shape, and the way it inserts in the bottom bar is reminiscent of Google Tasks. You can see how it looks in both white and dark mode in the screenshots below.
Left: Bottom bar now. Right: New UI in testing.
Nothing else appears to have functionally changed inside the app. The new look seems to be triggered server-side (I don't have it on any device, despite using the same Keep version) but appears to still require the latest release of Keep. You can download v5.19.451 of the app from the Play Store or APK Mirror, but remember you're still playing server-side roulette. You may get it or not.