The files that contain the .nfo file extension, are the text files containing information about a pirated application that has been downloaded to a computer hard drive from the Internet. These NFO files are often referred to as "readme" files. These file hold the text about the software, release notes, the group who distributed the program and the related files. NFO files usually contain ASCII text identifying the piracy group. NFO readers such as NFOPad can extarct the text characters as the intended graphic. Important: As Mac' System Information tool also uses the ".nfo" file extension, Mac may not be able to open NFO files in the System Information viewer. It would be better to open the files directly in some text editor or a NFO viewer.