Game concept · All Under Heaven
Reverence Decree
The game also links it as Reverence.
From the game's encyclopedia
The Reverence Decree mandates that the Mandala Subjects focus their efforts on furthering spirituality and worship.
Pilgrimages, rituals and Piety are the cornerstones of this Mandala Decree.
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.
Reverence Decree is an entry of Crusader Kings III's in-game encyclopedia (All Under Heaven). The game explains it: "The Reverence Decree mandates that the Mandala Subjects focus their efforts on furthering spirituality and worship." It is part of Mandala Decree. The game also links it as Reverence. 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.