Если знаете букву, на которую начинается нужное расширение - выберите ее.

.FGD расширение

Тип файла Forge Game Data File
Разработчик Valve
Категория Файлы игр

Описание формата файла

Game definition file used by Hammer Editor, a component of the Source SDK used to make map files for Valve games; describes all entities used by a game; enables game modifiers to reference game entities when creating custom game modifications.

FGD files are available for popular Valve games, such as Half-Life, Counter-Strike, and Team Fortress Classic.

NOTE: The Hammer Editor program was originally developed using the name "The Forge," which was used as the basis for naming FGD files.

Программы, которыми можно открыть файл .FGD

Windows
Valve Source SDK Описание