Game concept
Tax Decree
The game also links it as Tax Decrees.
From the game's encyclopedia
Each Tax Jurisdiction can have a different Tax Decree, modifying the Taxes and Levies contributed by its Taxpayers.
Tax Decrees will often change the Obligations in return of another penalty or boon.
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.
Tax Decree is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Each Tax Jurisdiction can have a different Tax Decree, modifying the Taxes and Levies contributed by its Taxpayers." It is part of Tax Jurisdiction. The game also links it as Tax Decrees. Patch 1.20.1.2, from game/common/game_concepts/03_fp3_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/03_fp3_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.