num_realm_holy_sites_faithful_holders

num_realm_holy_sites_faithful_holders = {
	$CHARACTER$ = { save_temporary_scope_as = root_scope }
	trigger_if = {
		limit = {
			exists = $CHARACTER$.confederation
		}
		custom_description = {
			text = direct_realm_holy_sites_held_by_faithful_confederation
			subject = $CHARACTER$
			object = this
			value = 1
			any_holy_site_barony = {
				county = {
					save_temporary_scope_as = current_holy_site
					is_holy_site_controlled_by = $CHARACTER$
					holder.faith = $CHARACTER$.faith
				}
			}
		}
	}
	custom_description = {
		text = number_realm_holy_sites_held_by_faithful
		subject = $CHARACTER$
		object = this
		value = $COUNT$
		any_holy_site_barony = {
			count >= $COUNT$
			county = {
				save_temporary_scope_as = current_holy_site
				OR = {
					is_holy_site_controlled_by = $CHARACTER$
					$CHARACTER$.confederation ?= {
						is_house_based = no # any_confederation_member is not performant for house blocs
						any_confederation_member = {
							scope:current_holy_site = {
								is_holy_site_controlled_by = prev
							}
						}
					}
				}
				holder.faith = $CHARACTER$.faith
			}
		}
	}
}

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