Game concept
Governance Issue Tier
The game also links it as Tier.
From the game's encyclopedia
Every Governance Issue has a Governance Issue Tier, which reflects the overall rewards of an Issue when successfully solved. Solving an Issue with a higher tier will typically result in larger amounts of Gold or Influence, as well as a greater amount of experience gained in the Governor Trait
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.
Governance Issue Tier is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Every Governance Issue has a Governance Issue Tier, which reflects the overall rewards of an Issue when successfully solved." The game also links it as Tier. Patch 1.20.1.2, from game/common/game_concepts/07_ep3_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/07_ep3_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.