defenders_of_highgod_decision_effects

defenders_of_highgod_decision_effects = {
	#Holy site building
	#if = {
	#	limit = {
	#		faith = {
	#			any_holy_site_barony = {
	#				count = 1
	#				county.holder = root
	#			}
	#		}
	#	}
	#	faith = {
	#		every_holy_site_barony = {
	#			limit = { county.holder = root }
	#			county.title_province = { defenders_of_highgod_decision_hall_of_heroes_effect = yes }
	#		}
	#	}
	#}
	#The scope has been saved before this effect is run
	scope:holy_site.title_province ?= { defenders_of_highgod_decision_hall_of_heroes_effect = yes }

	#Fervor, modifiers and holy_warrior traits	
	faith = {
		save_scope_as = highgod_faith_scope
		change_fervor = {
			value = medium_fervor_value
			desc = fervor_gain_defenders_of_highgod
		}
	}
	add_character_modifier = {
		modifier = defender_of_the_faith
	}

	if = {
		limit = { number_of_commander_traits < commander_trait_limit }
		add_trait = holy_warrior
	}

	custom_tooltip = defenders_of_highgod_decision_effects_holy_warriors_tt
	hidden_effect = {
		every_vassal_or_below = {
			add_to_list = warriors
		}
		every_courtier = {
			add_to_list = warriors
		}
		every_in_list = {
			list = warriors
			limit = {
				is_adult = yes
				is_ai = yes
				can_be_combatant_based_on_gender_trigger = { ARMY_OWNER = root }
				number_of_commander_traits < commander_trait_limit
				faith = root.faith
			}
			random = {
				chance = 50
				add_trait = holy_warrior
			}	
		}
	}
}

As written in game/common/scripted_effects/00_major_decisions_scripted_effects_2.txt.