There is only one file type that uses the .WGF extension:
Widelands Game File
Saved game created by Widelands, an open source strategy game where players build settlements and battle other tribes; contains the initial saved state for a game; used to record the starting conditions for a game.
After beginning gameplay, WGF files are saved with a corresponding .WRPL file, which records all player commands from the starting condition. WGF files can also be seen with the multiple file extension .WRPL.WGF.
Updated: November 5, 2009