This article explains two file formats that use the FSB file extension. It also explains how to open both file formats, and how to convert your file to another file format.
A file with the fsb file extension is an FMOD Sample Bank Format file. These files store sound information, such as music and speech, for video games designed for popular console systems such as the Xbox, PlayStation, and others.
When an FMOD project file (.FDP) is created, an FSB file is created at the same time as an FMOD Audio Events file (.FEV).
If your file is not used with video games, it is likely a Form-Z Compiled Script file that stores plugins compiled from a Form-Z Script file (.FSL). They are normally delivered as a ZIP archive.