.cfg File — Configuration File

CFG is a generic configuration file extension used by a wide variety of software applications to store settings, preferences, and parameters. CFG files typically use simple text formats — key=value pairs, INI-style sections, or application-specific syntax. The .cfg extension is one of the oldest and most commonly used configuration extensions in computing, found across operating systems and application domains. Examples include Python's setup.cfg (project configuration), Buildout's buildout.cfg, game engine configuration (id Software's Quake/Doom .cfg files), network equipment configuration (Cisco IOS .cfg), and application-specific settings files. Because .cfg is a generic extension with no standardized format, the actual syntax varies entirely by application — some use INI format, others use XML, JSON, custom syntax, or simple key-value pairs. The lack of a standardized format means that CFG files require knowledge of the specific application to interpret correctly. Despite this ambiguity, the .cfg extension persists because it clearly communicates the file's purpose (configuration) to both humans and file managers, making it useful for organizing application settings alongside source code and data files.