It's the treasure of the Sierra, madre!
Actually, another thing happened today. Notification Center told me that there was an update available. It turns out that it was iTunes 12.5.3. I installed that one yesterday but, what the heck, I did it again. As before, AppStore did not list any updates from the last 30 days.
I don't know if this update was a small one because, when I launched iTunes and selected About iTunes, the version listed was 12.5.3.17.
