All UTIs for packages must inherit from com.apple.package
I had a devil of a time trying to get Xcode to recognise my standard Core Data UIManagedDocuments, given they are bundles, not flat files. Turns out one of the keys was the your UTI must inherit from com.apple.package. I had rather more sensibly (IMHO) inherited from one of the built-in database UTIs. Silly me for … Read more