We already have sysutils/apc-upsd which hasn't been maintained upstream
in >10 years, which I intend to rm unless there are objections.
From maintainer Kirill Bychkov with various input from myself.
Apcupsd can be used for power mangement and controlling most of APC's
UPS models. Apcupsd works with most of APC's Smart-UPS models as well as
most simple signalling models such a Back-UPS, and BackUPS-Office.
During a power failure, apcupsd will inform the users about the power
failure and that a shutdown may occur. If power is not restored, a
system shutdown will follow when the battery is exhausted, a timeout
(seconds) expires, or runtime expires based on internal APC calculations
determined by power consumption rates.