Stores regions and markers information about a specific sound file; created automatically by Sound Forge Pro when user edits have been made to a sound file; saved in the same directory as the corresponding audio file with the same name, but with a "*.sfl" extension.

Newer versions of Sound Forge save the audio waveform image in a .SFK file. Neither SFL or SFK files store actual audio data, but are saved along with the audio file. Sound Forge Pro was previously developed by Sonic Foundry, but is now developed and distributed by Sony. NOTE: Sound Forge Pro was previously developed by Sonic Foundry, which was acquired by Sony in May, 2003. Sound Forge Pro was then acquired by MAGIX in 2016.