The file or folder you're viewing is located on a file server or is being
shared under System 7. To allow both MS-DOS computers and Macintosh
computers to access file servers, all files and folders are named twice.
Since MS-DOS limits both the length and the kinds of characters in
file and folder names, we have to change the standard Macintosh names to
shorter versions that work under MS-DOS. Clicking on the file or folder
name in the Get Info dialog box toggles between the Macintosh and MS-DOS
versions of the name.
Examples:
Macintosh name = System Folder Short name=!System.Fol
Macintosh name = Cafe 7.0F Short name=!Cafe_7.0F