2004 Chevy Cavalier Name of the hose that contains the blee

I have an 04 cavalier that started overheating after running out of coolant. I fixed everything associated with the problem, but when bleeding the system to check for air pockets the head snapped off of the bleeder screw. I can't find anywhere the name of the line or hose that the bleeder screw is located on. On the engine, its located beside the engine block on the driver side, directly under the spark plugs. I'v heard this called the "cooling system purge line" and the "heater return hose". I tried drilling and tapping to extract the screw but that didn't work. Any ideas on the getting the screw out or which part I need would be helpful.

Thanks for the help