Why does Forno Bravo pizza ovens have the chimney at the center of the dome?

[rajhlinux]

Hello,

Why does Forno Bravo pizza ovens have the chimney at the center of the dome?

Also why do they have such a big forehead that looks like a cap?

[Gulf]

The FB ovens vent from the entry and squirrel tail over the dome to the center of the dome from the outside of the cooking chamber. Not sure what you mean by a big "forehead that looks like a cap" unless you are referring to the inset to the entry that helps keep rain and snow out.