Having nothing better to do just now, I decided to check for Windows Updates.
Much to my surprise, I was told that KB5004476 was downloading and would be installed.
After my machine had rebooted, I checked my Update History and found that two updates had actually been installed:
KB5004476 (OS Builds 19041.1055, 19042.1055, and 19043.1055) Out-of-band
(https://www.windowslatest.com/2021/06/12/windows-10-kb5004476-emergency-patch-released-to-fix-xbox-issues/)
and
KB4023057: Update for Windows 10 Update Service components
The latter has been the subject of much criticism, so I uninstalled it.
Any comments or observations?