Assuming that air breather = air filter, the purpose is to filter the incoming air, and remove the dirt, dust, sand, grit, and grasshoppers that could otherwise find their way inside the engine and cause premature wear. As far as the location, it is located inside the big black plastic box that sits behind the battery, and is connected via corrugated plastic tubes to the air intake manifold on top of the engine, and also to the inside of the driver's fender. This assumes that you have a stock, unmodified air intake system.
