This short (11-inch) power cord shipped with a later version of the Xserve or the Xserve RAID, a rack-mount server from Apple produced from 2002–2009. This short power cord was ideal for a rack-mounted server to conserve both rack space and weight.
The Apple Xserve had the ability to house two power supplies so there was redundancy in the event one power supply failed. According to one of the Xserve User Guides:
Power supply and power supply bays—A removable power supply for the Xserve. The power cord connects here. You can install two 750- watt power supplies for redundancy; either supply can take over the full load for the Xserve if the other supply fails or is removed.
The original Xserve User’s Guide specifies that it only ships with a long power cord: “You can use the long power cord supplied with the server, or another cord…” Thus, this power cord likely shipped with a later Xserve model. The Xserve RAID User Guide acknowledges that the Xserve RAID may have shipped with more than one type of power cord (“If you received more than two power cords, use the ones with plugs compatible with the electrical supply for your location.”)