What software? Alert says "software update is required to connect" my iPhone to Mac

Several times when I plugged in my iPhone to my Mac recently, I get this alert on my Mac:

But my MBP 11,1 connects to my iPhone 8, no sync or update problems. Still, a few days ago, when I received this alert the first time, I clicked the Install button and get a "Downloading 1 item" progress window followed by "Installing 1 item" progress window that takes several minutes. I've re-started my Mac and iPhone at least once since then and just got this alert again so installing the mystery "software update" doesn't avoid the alert.

What is this "item" that is downloaded and installed?

The alert has a button to "Learn More..." that goes to this outdated and inaccurate webpage, updated in Jan 2020:

https://support.apple.com/en-us/HT208831

"If your iPhone, iPad, or iPod touch has a newer version of iOS than is supported by your Mac, you may see this alert" but macOS 10.15.7 supports iOS 14.2.

Then the alert oddly says, "If you continue to see this alert, make sure that your software on your Mac and iTunes are up-to-date." Well, I continue to see this alert but iTunes was replaced by Music desktop app, and is now at 1.0.6 so I'm up-to-date but this webpage is still living in iTunes era.

Anyone else getting this alert that's all up-to-date and having no problems except seeing this alert?