.UNF File Extension
What is a UNF file?
Game ROM created from Nintendo Entertainment System (NES) or Famicom video games; opened and played on a computer using the Nestopia emulator.
The UNF ROM file is saved in the Universal NES Image Format (UNIF) as an alternative for storing NES and Famicom images. It was originally developed by Tennessee Carmel-Veilleux but then abandoned in 2008. In 2011, the UNIF format was then added to the libunif project and has since been maintained.
NOTE: The .UNIF file extension is also used to store NES and Famicom ROMs but is not as common as the UNF extension.