this is true, ive always found it really odd. what on earth do they coat it in?!
still, its tasty so i eats it.
I work (part time) on a the bakery in the local Sainsbury's, the topping is basically a paste made with (mainly) rice flour. I think there's a bit of olive oil in there too. Not sure.
And yeah, if you think it smells bad after baking, try a whiff of the paste

Edit: I made a giant one once. It was awesome.