A "crack" is a modified executable file designed to bypass Digital Rights Management (DRM) such as CD-key checks or online authentication.
: Applying these often requires creating a portuguese folder within the game directory and editing the stemu.ini configuration file to point to the new language. Call of Duty 4: Modern Warfare Crack [PT-BR]
At launch, the original 2007 version did not officially support Portuguese. The "PT-BR" designation in community circles typically refers to unofficial localization efforts: A "crack" is a modified executable file designed