One of the enduring problems in working with computers is embodied in the question: What does this data represent? On the Mac, this question gets asked in several places: when a file is opened from Finder, when data is copied off the pasteboard, when a file is indexed by Spotlight, and when a file is viewed through Quicklook. Thus far, there have been several answers: file extensions, creator codes, MIME types.
Apple has decided that the long-term solution to the problem is universal type identifiers (UTIs).
A UTI is a string that identifies the type of data.
This data may be in a file or in a memory buffer.
UTIs are organized hierarchically.
For example, the UTI
public.image conforms ...