5–6 player extension: official expansion adding hexes, pieces and a special build phase.; Seafarers, Cities & Knights, Traders & Barbarians: official expansions that substantially change the game.; Beginner layout: the fixed setup printed in the rules, recommended for a first game.
Why people argue about this
People often assume that the 5-6 player extension is a house rule when it's actually an official expansion, leading to misunderstandings about its status and compatibility with other expansions like Seafarers or Cities & Knights. The confusion arises because these variants are clearly marked as "official" in the rules but might be overlooked due to their brevity compared to other content.
