INI is the default extension of Windows and applications configuration files. The INI files hold configuration settings and switches and permanent application settings. INI files are ASCII text files that can be edited with any ASCII text editor such as Notepad. The INI files are a holdover from Windows 3.1 since starting with Windows 95 most configuration switches are stored in the Registry. However many Windows applications still use the general Windows WIN.INI file or the application specific INI file.