Game concept
Budget Category Trend
The game also links it as Trend.
From the game's encyclopedia
The difference in Treasury that a Budget Category will receive compared to the previous budget enactment.
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.
Budget Category Trend is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "The difference in Treasury that a Budget Category will receive compared to the previous budget enactment." It is part of Treasury Budgeting. The game also links it as Trend. 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.