Game concept
Scheme Advantage
The game also links it as Advantage, Scheme Advantages, Advantages.
From the game's encyclopedia
Advantages represent progress made towards the goal of a Scheme. They can be spent to convince Agents to join a Scheme, or to execute one with an increased Success Chance.
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.
Scheme Advantage is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Advantages represent progress made towards the goal of a Scheme." It is part of Scheme. The game also links it as Advantage, Scheme Advantages and Advantages. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.