gtk:widget-font-map (widget)

widget -- a gtk:widget object
fontmap -- a pango:font-map object, or nil to unset any previously set font map

The gtk:widget-font-map function gets the font map that has been set. The (setf gtk:widget-font-map) function sets the font map to use for Pango rendering. When not set, the widget will inherit the font map from its parent.