If you’ve ever found yourself staring at file type you just don’t recognize or know what to do with, then the File Extension Library might be able to help.

Have you ever been sat looking at a ctt file and wondering what the hell it was? Whether it was safe to delete or should you keep it? Now you can find out that the file in question is a Windows Live Messenger file, usually associated with contacts.

So whether it is a ctt file or you find yourself with a DJVU file (a raster image file), then you know to head on over to the file-extension-library.