Complex sentence: Today, the great majority of the cardinals are archbishops of the main metropolitan dioceses of the world, who reside in their countries, and except the exclusive right of the election of the new pope their dignity is purely honorific.
Split into simpler sentences: Today, the great majority of the cardinals are archbishops of the main metropolitan dioceses of the world, who reside in their countries. Apart from the exclusive right of the election of the new pope, their dignity is purely honorific.