add_hook_from_temp_de_jure_liege_to_attacker

add_hook_from_temp_de_jure_liege_to_attacker = {
	# Assumes scope of title to be conquered.
	# Assumes scope:attacker to be set for the character initiating the war.
	# Assumes scope:temp_de_jure_liege to be set for the de jure liege that
	# might gain a title from the war.
	# Outcome: De jure liege of the contested title will owe a favor towards
	# the attacker of the war if the de jure liege is in the vassal tree of the attacker.
	if = {
		limit = {
			exists = scope:temp_de_jure_liege
			scope:temp_de_jure_liege != scope:attacker
			scope:temp_de_jure_liege = { target_is_liege_or_above = scope:attacker }
			scope:temp_de_jure_liege = {
				is_ai = yes
			}
			scope:attacker = {
				can_add_hook = {
					type = favor_hook
					target = scope:temp_de_jure_liege
				}
			}
		}
		scope:attacker = {
			add_hook = {
				type = favor_hook
				target = scope:temp_de_jure_liege
			}
		}
	}
}

As written in game/common/scripted_effects/00_casus_belli_effects.txt.