UTIs are nicer than mime types in that they allow a simple way to make up a unique name you control (java style com.myurl.myformat) and in that there is an inhe

UTIs are nicer than mime types in that they allow a simple way to make up a unique name you control (java style com.myurl.myformat) and in that there is an inheritance mechanism (you can say com.myurl.myformat also is a sqlite database, for example). But unless I misunderstand something the fundamental problem of figuring out what particular logical type some collection of bytes on your disk has is in fact not solved at all, because the UTI is not stored together with the file in the filesystem (unless I'm misunderstanding something). As far as I can tell macOS, apart from a few places like the clipboard, basically just takes a guess based on registered file extensions (or, for rest calls, the mime type) -- is that not so?