--extra-socket name
              Also listen on native gpg-agent connections on the given socket.
              The intended use for this extra socket is to setup a Unix domain
              socket  forwarding  from  a remote machine to this socket on the
              local machine.  A gpg running on the  remote  machine  may  then
              connect  to  the local gpg-agent and use its private keys.  This
              allows to decrypt or sign  data  on  a  remote  machine  without
              exposing the private keys to the remote machine.