Game concept
Mandate
The game also links it as Mandates, Mandate's, Mandates'.
From the game's encyclopedia
Mandates are useful tasks a Liege can set for their Diarch when Sharing Power.
Similarly to Councillor Tasks, the Liege selects a Mandate and then slowly receives benefits from it.
When a Diarch does their job well, they both swing the Scales of Power towards themselves and generate Strife with their fellow Vassals.
How much benefit the Liege receives depends on their Diarch's Diarch Aptitude and Loyalty.
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.
Mandate is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Mandates are useful tasks a Liege can set for their Diarch when Sharing Power." It is part of Regency. The game also links it as Mandates, Mandate's and Mandates'. Patch 1.20.1.2, from game/common/game_concepts/04_ep2_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/04_ep2_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.