antiquarian_improve_artifact_effect

antiquarian_improve_artifact_effect = {
	if = {
		limit = {
			artifact_slot_type = primary_armament
		}
		primary_armament_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = armor
		}
		armor_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = regalia
		}
		regalia_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = helmet
		}
		helmet_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = throne
		}
		throne_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = wall_big
		}
		wall_big_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = wall_small
		}
		wall_small_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = sculpture
		}
		sculpture_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = book
		}
		book_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = pedestal
		}
		pedestal_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = miscellaneous
		}
		miscellaneous_improvement_effect = yes
	}
	else_if = {
		limit = {
			artifact_slot_type = journal
		}
		journal_improvement_effect = yes
	}
}

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