Datafork TrueType

Datafork TrueType is a font wrapper used on Apple Macintosh computers running Mac OS X. It is a TrueType suitcase with the resource map in the data fork, rather than the resource fork as had been the case in Mac OS 9. It uses the file extension .dfont.
Mac OS X Snow Leopard.
In Mac OS X 10.6, released August 28, 2009, the dfont format is being (gradually) replaced with the TrueType Collection format.