GtkButton labelled by an image is somewhat pointless
Maybe that there was a reason for doing that, but if you call gtk_button_set_icon_name, the button gets a labelled by relation to the icon which has no underliing accessibility label, so the fallback logic assigns it a name of GtkImage, which is then added after any label which might be set to the button itself. I would most likely remove the relation in that case, but i'm asking before proposing a merge request whether the relation has any other reason/purpose?