Everybody has heard of a "barn find". The story is you find a rare vehicle in an old barn and buy it for little or nothing. Same deal here but with a different vehicle. My buddy finds all kinds of orphan planes and this one was a throw away. Plug cut off the ESC, no information on what kind of receiver, if any, and how to access it. Fortunately, Youtube has enough videos that you can probably find out anything.
After that it was just like building any plane. New receiver, new ESC and assigning channels and creating the necessary mixes.
Here's my "barn find" which I dedicate to Mr. NCT who shared his foam board design of the same plane some time back.