An accidental push of an internal Windows 10 Insider build may have given us a glimpse of what Microsoft is planning for the future of the Start Menu and the Emoji Panel. Microsoft accidentally released an internal build 18947 to Insiders on all rings this week by accident. The leaked build was meant to be used exclusively by Microsoft developers. There is no guarantee that these features will ever make it into a final version of Windows 10. Microsoft has posted instructions that you can use to revert to the correct version of the Windows Insider program.
Source: https://www.bleepingcomputer.com/news/microsoft/leak-of-internal-windows-10-build-gives-a-peek-at-new-features/