neowin[.]net/news/microsoft-quietly-installing-kb5001716-windows-1110-update-for-the-good-of-your-pc/
KB5001716 is an update to Windows Update. Like some of the updates to Defender, Microsoft uses the same KB number for different updates released on different dates. It is not available in their online update catalog. Google and you'll find lots of references to problems installing an update with the same KB number/name in the past --
bleepingcomputer[.]com/news/microsoft/windows-10-kb5001716-update-fails-with-0x80070643-errors-how-to-fix/
This time the stated purpose of the update is to help Microsoft force upgrade Windows versions that are about to lose support. Microsoft however also adds this:
After this update is installed, Windows may periodically display a notification informing you of problems that may prevent Windows Update from keeping your device up-to-date and protected against current threats. For example, you may see a notification informing you that your device is currently running a version of Windows that has reached the end of its support lifecycle, or that your device does not meet the minimum hardware requirements for the currently installed version of Windows. [emphasis mine]