If you are looking for specifically "6.1" content, it likely pertains to these releases:
The content related to likely refers to historical versions of the popular A Game of Thrones total conversion mod for Crusader Kings II . While the mod eventually progressed to version 2.2 and beyond, version 0.6.1 and 1.6.1 were major milestones in its development. Core Mod Features Agot Ck2 6.1
: Players can lead noble houses, the Night's Watch, or merchant republics in Essos. Significant Early Versions If you are looking for specifically "6
: Allows players to start at various points in history, such as Aegon's Conquest, the Dance of Dragons, or Robert's Rebellion. Significant Early Versions : Allows players to start
: Includes mechanics for dragons, White Walkers, Valyrian steel artifacts, and one-on-one duels.
: A custom mechanic for handling large-scale civil wars.