I'm not sure what the actual files were, I was moving my iTunes library from a mac over to a PC running MusicBee. The mac had 305gbs of songs, but when I dragged the songs over on an external drive and then to MusicBee, it read as over 350gbs. I deleted all the 4kb files that had no metadata, track/artist name, and the size was back to 305 gigs. I'm not exactly sure what files they were.
Does that help?