Game concept
Unmanaged Holdings
The game also links it as Unmanaged Holding.
From the game's encyclopedia
These are disabled Holdings that do not count toward your Domain Limit.
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.
Unmanaged Holdings is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "These are disabled Holdings that do not count toward your Domain Limit." The game also links it as Unmanaged Holding. Patch 1.20.1.2, from game/common/game_concepts/mpo_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/mpo_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.