gnuserv allows you to attach to an already running Emacs.  This allows
external programs to make use of Emacs' editing capabilities.  It is
like GNU Emacs' emacsserver/server.el, but has many more features.

This is the gnuserv part of XEmacs split out for use in GNU Emacs.  If
you use XEmacs you do not need this package.

Homepage:
https://www.emacswiki.org/emacs/GnuClient
