a) submitting the received request in an unmodified form to the application on {HEAD ~ behalf} of {TAIL ~ the client device} and receiving output from the application responsive to the submitted request 
of
a ) submitting the received request in an unmodified form to the application on { HEAD ~ behalf } of { TAIL ~ the client device } and receiving output from the application responsive to the submitted request
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH