Game concept
Duel Edge Bonus
From the game's encyclopedia
As Characters Duel, they may gain temporary advantage, such as by leveraging Terrain or special Traits. This increases their Prowess for the duration of the current bout, and is lost immediately after.
The opposite of Duel Edge Bonus is Duel Edge Penalty.
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.
Duel Edge Bonus is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "As Characters Duel, they may gain temporary advantage, such as by leveraging Terrain or special Traits." It is part of Single Combat. 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.