credits for this go to player tambardo from EU server, who found it. There is apparently an easter egg on the Kharkov map. When you destroy one of the garages in the A3 sector, inside, you will find a strange vehicle.
This is the Chtz armored tractor (bronetraktor), built in Kharkov in some numbers as a stopgap measure in 1941, when the Soviets desperately tried to put guns on pretty much everything to stop the Germans. Its low quality model exists in the game for quite some time – for purposes unknown. It’s doubtful it will ever be introduced.
This vehicle appeared once already in March in the developer diary videos.