Game concept
Treasure Map Contract
The game also links it as Treasure Map Contracts, Treasure Map Contract's, Treasure Map Contracts'.
From the game's encyclopedia
Bring an old and withered adventurer to find their final treasure.
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.
Treasure Map Contract is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Bring an old and withered adventurer to find their final treasure." It is part of task_contracts. The game also links it as Treasure Map Contracts, Treasure Map Contract's and Treasure Map Contracts'. Patch 1.20.1.2, from game/common/game_concepts/07_ep3_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/07_ep3_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.