Game concept
Aftermath
From the game's encyclopedia
The Aftermath phase of a Battle occurs whenever one side has won. The victor will attempt to run down as many Retreating Soldiers as possible.
Men-at-Arms with high Pursuit are able to kill more Soldiers during the Aftermath, while Men-at-Arms with high Screen will protect friendly Soldiers.
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.
Aftermath is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "The Aftermath phase of a Battle occurs whenever one side has won." 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.