In Belfort: The Expansion Expansion, the King has requested that the architects build expansions to their existing buildings. Because this sounds like extra work, the King has decided to allow the architects use his Assistants!
These expansions open up new and individualized scoring paths for players as they expand their own properties. Assistants are chosen in reverse turn order every round and can either help you with their own unique ability (which changes every season), or can be used to acquire a new permit for an expansion.
Belfort: The Expansion Expansion also comes with new guilds, some of which can be used with only the base game and others that require the components in this expansion.