INI is a family of simple text-based formats, commonly used for configuration files. INI files consist of lists of key-value pairs (separated by equals sign) grouped in sections (denoted by square brackets).
The INI format was popularised by early versions of Windows; Windows 95 introduced the Registry as the replacement. Variants of INI remain in use to this day, including on other platforms;
.gitconfig files and systemd configuration files use INI-like formats.