Klas is right, it was a triple mount with surplus
Luftwaffe MG 151 (1.5cm) and later MG 151/20 (2cm).
The MG 151 was initially used in the Bf-109 F-2 as its central "motor cannon". The Germans found that HE content to be far more effective than high velocity penetration. They "necked out" the 15mm cartridge to 2cm and shortened it so the total round was the same length and made the MG 151/20. The barrel and a few parts were different but most of the gun remained the same. The MG 151/20 was used from the Bf-109 F-4 onwards. Neither had any relationship to the earlier 2cm MG FF design as used in many aircraft like the Bf-109 E. The projectile, though, from the 2cm MG FF was used in the MG 151/20 but with a mutated MG 151 cartridge. Some early Fw-190 A series had 2 each of MG FF and MG 151/20 but later models had 4 MG 151/20.
The MG 151 had very limited use, the MG 151/20 became the commonest German 2cm aircraft cannon but by late '43 the Germans wanted more HE punch and decided to go to 3cm. They had 2 3cm, the MK 103 which was quite heavy and the MK 108. The MK 103 was used in aircraft like the HS 129 and night and heavy fighters and a pair as the armament of the Pz IV
Kugelblitz unrealised AA design. It was far too heavy for single seat fighters with the exception of the Do 335. The MK 108 though firing a similar projectile, did so at a much lower velocity and the low gun weight meant that it could replace MG 151/20 installations. So early Bf 109 G6 could have 2 1.3cm MG 131 and a 2cm MG 151/20 motor cannon and late Bf 109 G6 could have 2 MG 131 and a 3cm MK 108. 4 MK 108 were fitted to the Me 262. So first with the MG 151/20 replacing the MG 151 and later the MK 108 replacing the MG 151/20, the earlier guns, those older guns became available for other use.
So while the 2cm FlaK 38/KwK 38 was fairly major rewrite of the FlaK 30/KwK 30 to increase its reliability and rate of fire, it had nothing to do with the
Luftwaffe MG FF and MG 151/20 who in turn were unrelated to each other.
I have seen a fair few light twin MG 34 7.92mm AA mounts. In "Da Paul Challenge" someone posted a multi MG 34 mount with 3/4 layers of MG 34 for something like 14 MG 34, captured by a Soviet (Naval?) infantryman. I found it difficult to count due to the photo quality and angle, so many protruding bits! I also have a vague memory of a quad MG 34 mount, not very common.
The Finns did capture about 80 Soviet 4 gun mounts. Those were 4 x 7.62mm Maxim M1910 MG mounted on a tripod+cone base. The cone shape seems to be a cooling water reservoir. The Finns called them ItKk/09-31. Apparently 70 survived the war. The heavy mount could be ground mounted but was often seen on the back of a truck, see SVN 43 & FVN 22 GAZ-4M-AA. Due to its weight the ground version was more often seen in cities, airfields and bunker complexes. Some were mounted in modified railway wagons, but its most common field use was on the GAZ-AA truck as the GAZ-4M-AA (the AA was the truck model, a licenced Ford-AA).
https://www.jaegerplatoon.net/AAMG.htm
No official counter for the ground version, yet. As far as I know there was no wheeled limber for the ground mount (such as the Flak 30/38 had). The whole thing had to be lifted onto a truck/wagon/sledge or carried by a few very strong men.
Edit: For the ground version the designation was M-4 during wartime, though some later called it the ZPU(-4), though that can cause confusion with the post war ZPU-4 with 4 x 14.5mm MG. I eventually found its weight of 470 Kg, about 43% of the US M45 Maxon quad .50" mount or roughly the weight of the Soviet 45mm AT (45L). By comparison the French twin 13.2mm weighed 300 Kg. I would suggest treat the same as the 13.2 CAJ mle 30 (FON 18) with Tow NA and a M of M(6) due more to the awkwardness of moving it than its weight.