religious_cb_holder_under_target_can_be_vassalized

religious_cb_holder_under_target_can_be_vassalized = {
	conquest_cb_holder_under_target_can_be_vassalized = yes

	# Religious Tolerance Check
	OR = {
		# For all Faiths, if the attacker views this vassal's faith more favorably than the defender does, they are 'liberated' and become vassals under the attacker.
		# For example, if Catholics are crusading against Ash'aris(viewed as Evil), any Messalian vassals (viewed as Hostile) will become vassals under the Catholic attacker.
		scope:attacker.faith = {
			faith_hostility_level_comparison = {
				prev.holder.faith < scope:defender.faith
			}
		}

		# Pluralist faiths always attempt to preserve vassals if possible, even if the vassal follows an Evil faith.
		scope:attacker.rite = { rite_has_parameter = pluralism_pluralistic_holy_wars_preserve_vassals }
	}
}

As written in game/common/scripted_triggers/00_war_and_peace_triggers.txt.