There is only one file type that uses the .XRNS extension:
Renoise Song File
Song format used by Renoise, a song creation program; stores data in a compressed .ZIP format that includes a Song.xml file and a SampleData folder; song information is stored in the Song.xml file, while samples and instruments are stored in the SampleData folder.
Samples stored within XRNS files may be saved in .WAV, .AIF, .OGG, .MP3, .AAC, or .FLAC formats. Since this data is stored in a standard .ZIP archive, the audio files can be extracted using a file decompression utility.
XRNS is short for "Extended Renoise Song."
Updated: November 7, 2009