GlobalUserInterface.CompositeFont

WPF composite font

A .compositefont file defines a composite font for WPF, the Windows Presentation Foundation. The XML file maps Unicode ranges and languages to real font families. The framework uses it for font fallback, thus text with mixed scripts renders completely. Windows ships files such as GlobalUserInterface.CompositeFont. Applications can add their own composite fonts.

A file extension is only a part of the file name. It does not give a guarantee about the format or the content of a file. But on Windows, the extension selects the program that opens the file.