Game concept
Travel Option
The game also links it as Travel Options.
From the game's encyclopedia
An option you pick when planning your Travel to enhance or modify the journey you are about to set out on.
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.
Travel Option is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "An option you pick when planning your Travel to enhance or modify the journey you are about to set out on." It is part of Travel. The game also links it as Travel Options. Patch 1.20.1.2, from game/common/game_concepts/04_ep2_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/04_ep2_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.