What is the random code in the comments box on imported CDs into iTunes?

When right clicking a file in iTunes, and clicking on "get info", there is all this random code in the comments box. I've noticed this only seems to for songs from imported CDs.

If I delete it, it doesn't seem to have any effect, so I'm just wondering what is it?

Note: It only only seems to show up in iTunes, if I right click -> properties, in windows explorer, there is merely a "0" there in the comments box.

Thanks