librenms-librenms/includes/discovery/os/apc.inc.php

<?php

$apc_desc = array(
    'APC Web/SNMP Management Card',
    'APC Switched Rack PDU',
    'APC MasterSwitch PDU',
    'APC Metered Rack PDU',
    'APC Embedded PowerNet',
);

if (str_contains($sysDescr, $apc_desc)) {
    $os = 'apc';
}

unset($apc_desc);