Open DDF File
DDF is a Diamond Directive File, hence the origin of the acronym DDF, and is used to specify the properties to compress a CAB extension file.
The Diamond Directive File specifications were created by Microsoft, for their CAB format.
The DDF file is stored in a plain text format, and should not be modified unless necessary, therefore we do not recommend opening it manually by the user.
DDF files are not placed inside the resulting CAB file. They only describe the settings to compress the resulting CAB file.