Open IWD File
IWD files contain the game data used by Call of Duty 2 (CoD2) and Call of Duty 4.
Call of Duty is a first-person shooter video game franchise published by Activision.
Since 2003 it focused primarily on games set in World War II.
Over time, however, the series has seen games set in the midst of the Cold War, futuristic worlds, and outer space.
The games were first developed by Infinity Ward, then also by Treyarch and Sledgehammer Games.
The IWD file may store graphics, weapons, scripts, or other information; it is compressed using ZIP compression to save disk space.
Most IWD files can be unzipped with a file unzip program like WinZip and edited with a text editor.
Manually opening IWD files is not recommended unless you know exactly what changes to make.
The above is in response to the fact that altering an IWD file can make it unusable by Call of Duty.