This is a 1:100 scale model for 15mm wargaming. The zip file contains two STL files, one for the turret and the other for the hull.
Fiat 2000 (15mm)
The Fiat Carro Armato 2000 was an Italian super-heavy tank, designed at the very end of WW1, but too late to see service in that conflict. It was, at the time of its design, probably the most powerful tank in the world.
Two of them were sent to Abyssinia, though they saw no active service and existed there primarily for propaganda purposes.