That's where .keycap is used nowadays.
*
* GtkFrame has a main CSS node with name frame and a subnode with
* name border. The border node is used to render the visible border.
- * The style class .flat can appear with the main node. In the
- * #GtkShortcutsWindow, frames are used with the .keycap style class.
+ * The style class .flat can appear with the main node.
*/
*
* GtkLabel has a single CSS node with the name label. A wide variety
* of style classes may be applied to labels, such as .title, .subtitle,
- * .dim-label, etc.
+ * .dim-label, etc. In the #GtkShortcutsWindow, labels are used wth the
+ * .keycap style class.
*
* If the label has a selection, it gets a subnode with name selection.
*