it's a link to a sound file.
.SF File Extension
TIP: Run a free scan for .SF file extension errors.
File Type IRCAM Sound File
Developer N/A
Popularity Average
Category Audio Files
File Description Sound file format developed by IRCAM, the "Institut de Recherche et Coordination Acoustique/Musique" (from France); used for storing CSound audio samples.
Program(s) that open SF files
Mac OS MixView Sound Sample Editor info
Any audio program or plugin that supports CSound samples info
Windows MixView Sound Sample Editor info
Any audio program or plugin that supports CSound samples
potentially includes a virus