Game concept
Liberty Faction
The game also links it as Liberty, Liberty Factions.
From the game's encyclopedia
The Liberty Faction seeks to lower the Government Authority and, if applicable, their own Vassal Contracts. If successful, their Liege will be unable to change the Government Authority of the Realm for some time.
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.
Liberty Faction is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "The Liberty Faction seeks to lower the Government Authority and, if applicable, their own Vassal Contracts." It is part of Faction. The game also links it as Liberty and Liberty Factions. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.