How do I know which application has the extension?
I got a message saying that the app with an extension may not work in the next operating system upgrade. I don't know which app that is refering to. How do I find it?
iMac 27″, macOS 10.15
Unless the message gave the app's name there's no way to tell. Anyway it's nothing to worry about at this time as the new system won't be released for some time. By then most developers who will be affected should be on board and have updates available for their apps.