The screenshots were posted and deleted by a "Microsoft engineer" but were preserved by FireCubeStudios on Twitter, and they suggest that Microsoft isn't reinventing Notepad in the style of more advanced apps like Notepad++ or Emacs.
The unfinished state of Windows 11's built-in apps was one complaint from our full review, and it's something that keeps the operating system from feeling fully modernized and unified.
Updates for apps like Your Phone, Microsoft Whiteboard, some kind of media player, and (now) Notepad have been leaked or announced but not released.
And other built-in apps like Wordpad still look like they did in Windows 7.
When available, the app updates will be downloadable from the Microsoft Store rather than Windows Update.