In the world of repacking, "FG" stands for FitGirl. This specific file contains the official game soundtrack (OST)
Optional bonus content archive (binary data file) fgoptionalbonussoundtracksbin
C:\Program Files (x86)\GameName\Bonus Soundtracks\ or in the game’s root folder under Extras\Soundtrack\ . In the world of repacking, "FG" stands for FitGirl
If the installer starts and immediately warns you that a .bin file is missing, it’s because you didn't download the optional soundtrack archive. In the world of repacking
This package contains the for the base game installation. These tracks include ambient scores, combat themes, and menu additions that were cut from the main installation to reduce the initial download size.