Game concept · All Under Heaven
Mandala Decree
The game also links it as Decree, Decrees, Mandala Decrees.
From the game's encyclopedia
The Mandala Decrees are the three Decrees mandated by the Mandala Ruler — signified by Prosperity, Expansion and Reverence.
Generally the Mandala realm has a very centralized authority, where the power over Subjects and Laws lies with the associated Ruler who can change them as required with little to no objection from its denizens.
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.
Mandala Decree is an entry of Crusader Kings III's in-game encyclopedia (All Under Heaven). The game explains it: "The Mandala Decrees are the three Decrees mandated by the Mandala Ruler — signified by Prosperity, Expansion and Reverence." It is part of Law. It covers Prosperity Decree, Expansion Decree and Reverence Decree. The game also links it as Decree, Decrees and Mandala Decrees. Patch 1.20.1.2, from game/common/game_concepts/tgp_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/tgp_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.