c_gtk_source_gutter_renderer_pixbuf_set_gicon

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
__gshared extern (C)
void function(GtkSourceGutterRendererPixbuf* renderer, GIcon* icon) c_gtk_source_gutter_renderer_pixbuf_set_gicon;

Meta