Windows 11 build 21990

Windows 11 build 21990 is the earliest known build of Windows 11 as of June 25, 2021. A screenshot of this build was posted on the "Inside Windows" Telegram by Zac Bowden, showing the search bar with "Windows Security" typed in. This build features the infamous "Do not take screenshots of this build" watermark. Also, it's possibly the first build which includes the Windows 11 GUI.