War Thunder tells me it's the "4th Tank Division", not sure how accurate that is.Yup, a Divisional marking - which one I can’t quite remember.
I'm guessing it's supposed to represent an Eagle of Saladin, the modern Egyptian heraldic symbol, and IRL seems to have been painted on IS-3s during parades for a time. That said, for all the attention it gets in the model-making community (since the IS-3 kits generally seem to come with that paint scheme as standard, I might still have that decal in a box somewhere), the Egyptian armored forces have from the 50's to the present had some of the coolest insignia and decals out there. Can't find a good picture atm but there was a Sherman unit marking from the 50's that had a chariot and archer drawn in the ancient style on it.