I see that drags from file promise providers contain metadata in a pasteboard type com.apple.NSFilePromiseItemMetaData. The type appears to be a property list, including keyed values such as "com.apple.pasteboard.promised-file-content-type".
Are these items documented anywhere, or are there system constants declared in public headers for them?
I don't feel too bad about taking advantage of them to discern the content of promised files, but it would feel better to know that they are intended for long-term use by developers.
Daniel