From Windows 11 gets a new desktop watermark on unsupported hardware (https://www.theverge.com/22988775/microsoft-windows-11-desktop-watermark-unsupported-hardware):
QuoteMicrosoft is pushing ahead with plans to warn Windows 11 users that have installed the operating system on unsupported hardware. In a new update to Windows 11, a watermark has appeared on the desktop wallpaper for unsupported systems, alongside a similar warning in the landing page of the settings app.
The new desktop watermark will state "System requirements not met. Go to settings to learn more."
(h/t ky331)