It's US Navy speak for "base model" or beta version. Lets say the navy buys a new boat. That first one will be the Mark 1, Modifications 0. If we added some aftermarket gun mounts it would be the Mark 1 Mod 1. New engines? Mark 1 Mod 2, etc. Lets say we'll order the next batch from the factory with the gun mounts and better engine from the factory. Now those would be the Mark 2 Mod 0. Get it? So that's me. Base model. What you see is what you get. Meat, cheese, bacon and bun. Everything else is just condiments...