Recently had this feature on an old Raleigh frame I built up fixed for my daughter- managed to pull through with a very long upholsterer's needle jabbed by trial and error into the old cable housing, which was also stuck inside. I used cable housing for the whole new cable- that's what my old uncle told me I should do and he is a cycling oracle. There were no cable stops on the top tube, so I guess the wire would wear on the tube edge at the point it entered the top tube otherwise.
My daughter said "Cool beans," when she saw it. I believe that means she liked it.