Catalina 10.15.2 has changed Gatekeeper’s dialogs to confuse notarization status

If you've updated to macOS Catalina 10.15.2 and installed any notarized apps since, you might have noticed that something has gone missing. Do you remember that dialog shown by Gatekeeper when you first open a notarized app, telling you that "Apple checked it for malicious software and none was detected"? Well, that sentence has now vanished. Instead, that dialog now looks very similar to the pre-Catalina dialog for non-notarized apps. I had to read this post twice to fully comprehend what was going on, but once you get it - and most of you will get it without multiple reads because you're not stupid like me - it's an interesting look at how seemingly subtle changes in security dialogs - especially undocumented changes - can actually have very serious consequences if you take them at face-value.