MacBinary is a standard format for binary transfer of arbitrary Macintosh documents. It combines both the resource and data forks (as well as the “Finder Info”) of a standard Macintosh file into a single data fork only file that can be stored on non-Macintosh machines.

Not commonly used on OSX - use .dmg or .sitx formats instead.

Home of the MacBinary specification [http://www.lazerware.com/formats/macbinary.html]