Game concept
Mongol Empire
From the game's encyclopedia
An Empire Title that can be created by a powerful tribal ruler on the Steppes. It enables the Mongol Invasion Casus Belli.
The title is created by taking the Become Greatest of Khans Decision.
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.
Mongol Empire is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "An Empire Title that can be created by a powerful tribal ruler on the Steppes." 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.