This was created for the Mac OS X operating system. Unlike the old operating environment versions, the font is stored in the thread of a data file instead of in resource threads. It’s been used as a container for TrueType fonts since 2009 after the release of Mac OS X 10.6, and is gradually replacing the TrueType Collection.
This format is used to store small personal icons. It is used in website development to create favicons that are displayed in the address bar of the web browser as well as in satellite TV for identifying broadcast channels. It is very similar in structure to a GIF format image.