powermgmt-base 1.36 (s390x binary) in ubuntu hirsute

 This package ships "on_ac_power" which lets you determine whether
 the system is powered from battery or an abundant supply. It's
 recommended to use this tool over a simple sysfs check,
 ConditionACPower or other ad-hoc methods which notoriously fail to
 account for unobvious quirks, both old and new.