MacOS choked while attaching new iPhone

I came to introduce my iPhone 12 mini to my Apple Silicon Mac laptop running 14.2.1. I opened Music, and plugged in the iPhone. I got a pop-up box, "A software update is required to connect to this iPhone." It didn't say what software was being updated, or where. But I agreed. It took a minute (in which the iPhone did not reboot) and then I got an error pop-up that said something like, "Some kernel extensions were installed that are not correctly signed" or "not trusted" or something along those lines. No action was recommended.  The name of the signer of those extensions was just some man's name, not a corporation. Unfortunately, I have not been able to get this error message to appear again, nor can I find those extensions under System Settings > Privacy and Security to enable or inspect them.

Thereafter, when I attach this iPhone, Music simply doesn't see it.  Nor does Finder. But Xcode does, so we don't have a problem at a hardware level. What to do next, where to look?