Looks like bypass lines for the throttlebody.
Tried visually tracing it.. Forget it... no way any hand fitting in there to even think of feeling it around... Could barely even get a 12" screwdriver in there to actually finally find the stupid intermittent leak.I believe that goes to the heater core. That would explain why it barley leaks. I imagine your not using your heater right now, so the heater core is closed and not flowing coolant.
Someone else needs to confirm this though.
Can you not feel where it leads? If it goes thru the firewall, it probably is.