Originally built for the UFO Supply Point. Ugly and bulky, without the slightest UFO:ish look. Consider it a failed attempt to build something of a ship with a bridge and all. Also a experiment with creating extendable devices in some way.
Propably this is just another captured design from some overrun civilisation. Seems to be used in low-priority missions as a transporter of cargo and personal, altough with an above-average amount of firepower.