In Settlers 6, there are a few game mechanics that are useless or simply for decoration, as extra content.
List of mysteries[]
Gem Maker's Hut[]
The gem maker's hut is a building that is only shown in the Harbor in Settlers 6: Eastern Realm. It has no workers and a Builder builds the building and upgrades it when gold is delivered to the harbor through a task. It
Village of Eastholm[]
There appears to be a village called Eastholm if you explore the map in both variations of Vestholm. In Mission 15, the village is hostile and delivers a knight in a prison cart to the harbor. However, in Mission 1, it is a Undecided faction. In the village, it has a barracks with mercenaries from the temperate climate.
Bandit trading[]
In Mission 15, the bandits show that they can trade stone and wood in the diplomacy menu.
Large Cathedral[]
In some maps, there is a larger version of the normal cathedral. It first appears in Geth and is the cathedral that is being built. The player has never had control over one.