There is only one file type that uses the .NRA extension:
Nero Audio Compilation
List of audio files compiled with Nero disc burning software; contains a playlist of tracks that can be burned to an audio CD; includes references to audio files, but does not contain actual audio data.
The contents of an NRA file may be viewed in a text editor, but since the file is not saved in a plain text format, it should not be modified.
Updated: November 23, 2009