has_changed_contract_obligation_trigger

has_changed_contract_obligation_trigger = {
	trigger_if = {
		limit = {
			scope:recipient = { government_has_flag = government_is_feudal }
		}
		custom_description = {
			text = "modify_vassal_contract_select_different_obligation_level"
			list_size = {
				name = changed_obligations
				value > 0
			}
		}
	}
	trigger_else = {
		custom_description = {
			text = "modify_non_feudal_vassal_contract_select_different_obligation_level"
			list_size = {
				name = changed_obligations
				value > 0
			}
		}
	}
}

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