What is a KFN file? File created by KaraFun, a program for editing and playing back karaoke music; saved in a proprietary format and contains MIDI audio as well. What is a KFN file? The KFN file type is primarily associated with KaraFun by RECISIO S. What is a KFN file? The file extension indicates to your device which program can open the file. Karafun is a popular karaoke player software that with its “editor” edition allows people to create backing tracks in KFN format. What is KFN file? The KFN file type is associated with 'KaraFun' software by RECISIO S.