With Filestar you get 0 different skills for working productively with Valve Game Cache File (.gcf) files.
About .Gcf
Name
Valve Game Cache File
Extension
.gcf
Format
Binary
Category
Game
Developer
Valve Corporation
Description
A Steam Game Cache File - the depot archive Steam used to deliver games like Half-Life 2 and Counter-Strike: Source before 2013. Filestar extracts its files and turns VTF textures into images.