[a/s] Door handles again

[John Hilty <hilty@xxxxxxxxxxxxx>]

I got to looking at my door handle, lock, deadbolt, etc. and wondered if
anyone can answer this. In the middle of the inside metal panel where
the door latch handle is mounted is a little metal post with a black
rubber or plastic cover on it. It is directly opposite the lock tumbler
on the outside. It doesn't move or appear to do anything. I have
sometimes wondered what it is for. Does anyone know?

Thanks,
John H.