The use of this axiom is extremely straightforward, it protects; all wonders made with the function to defend, guard, and protect against any harm is made with Prostasia. By default, there is only one function: To provide Armor. The more Prostasia a Genius get, the better the armor gets. If used on a vehicle or building, mundane or otherwise, receive Durability from Prostasia rather than Armor.
How the armor providing wonder is formed is something entirely different. With one simple function, it can come in every sort of form that helps fortify armor; from worn armor that requires no Mania to activate to shield generating wonders that can cover more area.