Game concept
Domicile Building
The game also links it as Domicile Buildings.
From the game's encyclopedia
All Domiciles can be upgraded with certain Domicile Buildings, which grant income, resources such as Prestige, and many other benefits to the owner.
The availability of buildings depends on the type of Domicile, as each type has a vastly different set of buildings.
Some Domicile Buildings can have Internal Upgrades.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Domicile Building is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "All Domiciles can be upgraded with certain Domicile Buildings, which grant income, resources such as Prestige, and many other benefits to the owner." It is part of Domicile. It covers Estate Building, Camp Upgrade, Ecclesiastical Estate Building, East Asian Mansion Building and Japanese Manor Building. The game also links it as Domicile Buildings. Patch 1.20.1.2, from game/common/game_concepts/07_ep3_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/07_ep3_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.