windowscentral[.]com/software-apps/windows-11/the-next-feature-drop-for-windows-11-is-coming-tomorrow-with-updates-to-widgets-and-the-taskbar
support.microsoft[.]com/en-us/topic/may-24-2023-kb5026446-os-build-22621-1778-preview-3c547100-7a73-4ae6-bb7d-ebd02e87dc04
Basically it's the 2nd, optional update of the month, but if you're desperate for something new, or if you're Microsoft and feel some need to show you're working hard to improve Windows, well, it's also Moment 3, a Much scaled down version of what used to be Windows Service Packs. It's not that big of a package, at just shy of 300MB, and includes several fixes along with the new features. Neowin published an article that's incorrect as far as I can tell, saying that your device has to meet the official requirements for Win11 before you're offered the update. Today I fired up the mini PC, which is Wayyyy out of spec for Win11, and the Moment 3 update was offered & installed just fine. [I was concerned because that would have meant that Microsoft might stop providing updates for all out of spec hardware running Win11, so I put it to the test.]
That all said, unless you get excited about stuff like a clock showing seconds, you can probably skip this one, waiting until it's included next Patch Tuesday.