The GK3 Barn Browser lets you open .brn files that ship on the GK3 CDs and view the contents of them, and extract the files within. Like WinZip, except for .brn files.
Requirements:
- Windows 98 or higher
- Microsoft .NET 2.0 or higher (download here)
The latest version is 2.0.2.0.
You can still get the older version at http://fwheel.net/gkbrowser.html