The metal line originally attached into the PCV valve in the forward valve cover. The other end, of course went into the breather canister. With engine torque, the line would pull the PCV valve out of the valve cover and spray oil. As TopNotch said, it was replaced by a short metal line that runs from the valve cover over to the air intake tube just in front of the throttlebody. It's completely mounted onto the engine so it won't pull out.
There is also a smaller metal line that runs alongside the large line. One end of it still attaches into the filter canister and the other has a rubber hose that goes to the big round end of the EGR solenoid, just to the right of the thermostat housing. Because of the need for the smaller line is likely the reason for the larger one still being there. They are attached to one another.