|Boolean values: yes or no, true or false, 1 or 0
If IvanBomb=yes is set on a warhead it will tell the game that the warhead is for Crazy Ivan's dynamite weapon, and so should attach timed dynamite to the target object rather than acting like a normal warhead.
If a unit is 'hit' by such a warhead it will not recognise that it has been hit and so will not retaliate (in the same way that the Spy's disguise-picker does not cause enemy targets to retaliate).
It should also be noted that warheads with IvanBomb=yes set will only attach dynamite to the target object if the weapon that invoked that warhead was fired by an InfantryType. If the weapon was not fired by an InfantryType then the warhead, and thus the weapon, will have no effect.
All additional affects on IvanWH are ignored however a ivan bombs can used against all airborne targets by changing the projectile.