Why are these applications marked as "Unknown", please?

All those except the first one is a part of AppleScript that was developed 31 years ago, before signing software was even a thing. Any Application that is created with the Script Editor, found in your Utilities folder, is going to show as Unknown because there is no signing capabilities. Even if you create your own Application with the Automator app, it will show as Unknown, since any application you create is not signed either. The first one, even though it is listed as an Application cannot be launched, sorry but I do not know the specific purpose.

I can confirm all those listed are part of MacOS and there is nothing nefarious with any of them.