IIRC, they were "gate guards" of the Reichstag, captured in Smolensk Russian during the Nazi Invasion. there are no accounts of their use during the battle, but the wrecks were found quite away's from where they'd been parked, and shot up pretty bad, suggesting that they'd been thrown into the fighting in some fashion.
odds are they were driven off and used as roadblocks and bunkers, but it is possible some desperate unit reactivated them figuring any tank is better than no tank.