This is a gamedata folder for S.T.A.L.K.E.R.: Shadow of Chernobyl. It only contains the "system.ltx" and "actor.ltx" files, which are editable. Note that you must modify the "fsgame.ltx" file, found in your STALKER directory, in order for any changes of these files to work in-game. Once you open the "fsgame.ltx", just change the "$game_data$ = false| true|" statement into this one: "$game_data$ = true| true|" (without the quotations). Cheers!