By default, all software supports multiple file extensions. GTK+ supports at least 3 different file extensions. The basic files that GTK+ supports are .GTKRC. However, not all of the extensions listed on the list are always used to save the effects of work in GTK+. Very often, files with such extensions are used as source data files used by GTK+.
GTK+ can be used to convert file formats between the file extensions listed below. You can open a file with one of the file extensions below via GTK+ and try to save it in another file format, also supported by GTK+.