You can export your image in XPM format, which is short for «X PixMap» format, when you choose the «.xpm» extension, or explicitly choose «X PixMap image» as file type in the export dialog.

This format is a successor for the older X BitMap format and supports color images. GIMP does not support setting an icon hot spot for this format.

There are no settings to choose from. No export dialog will open after you have chosen your filename. It will automatically start the export.