Associating file types with apps is one of the fundamental requirements of the GUI in macOS, and has been since the first Macintosh. UTIs form a global object taxonomy that generalises far beyond file types. UTI librarymacOS comes with a great many UTIs pre-defined to support many common types, and those used by bundled apps. An app’s Info.plist also declares any roles it assumes for specific UTIs, in this case as an editor of LogUI Log files with their custom UTI. Key pointsUTIs and file types are required to support the Finder and macOS GUI features, by associating file types with apps.