A 'config' file is a generic file extension used to store configuration settings for various software applications. These files typically contain parameters, settings, and preferences that control the behavior of a program. The format of a 'config' file can vary widely, ranging from simple text-based key-value pairs to more structured formats like XML, JSON, or INI. The specific structure and content are determined by the application that uses the file. Configuration files allow users to customize the application's behavior without modifying the program's source code. They are essential for adapting software to different environments, user preferences, and system configurations. These files are often human-readable, making them relatively easy to edit and understand, although incorrect modifications can lead to application malfunctions. They are a cornerstone of software flexibility and adaptability.