The convention is that no "Maintainer" means "Author" is the maintainer.
;; Author: Kenichi Handa <handa@gnu.org>
;; Naoto Takahashi <ntakahas@etl.go.jp>
+;; Maintainer: emacs-devel@gnu.org
;; Keywords: mule, multilingual, input method, i18n
;; This file is part of GNU Emacs.
;; Copyright (C) 1995-1996, 2001-2019 Free Software Foundation, Inc.
;; Author: Tomoji Kagatani <kagatani@rbc.ncl.omron.co.jp>
+;; Maintainer: emacs-devel@gnu.org
;; w32 Maintainer: Brian D. Carlstrom <bdc@ai.mit.edu>
;; ESMTP support: Simon Leinen <simon@switch.ch>
;; Hacked by Mike Taylor, 11th October 1999 to add support for
;; Authors: Kai Grossjohann <Kai.Grossjohann@CS.Uni-Dortmund.DE>
;; Alex Schroeder <alex@gnu.org>
;; Chong Yidong <cyd@stupidchicken.com>
+;; Maintainer: emacs-devel@gnu.org
;; Obsolete-since: 24.4
;; Keywords: convenience, wp
;; Copyright (C) 2001-2019 Free Software Foundation, Inc.
;; Author: Carsten Dominik <dominik@astro.uva.nl>
+;; Maintainer: emacs-devel@gnu.org
;; Old-Version: 1.2
;; Keywords: languages
;; Package: idlwave
;;
;; Authors: JD Smith <jd.smith@utoledo.edu>
;; Carsten Dominik <dominik@science.uva.nl>
+;; Maintainer: emacs-devel@gnu.org
;; Package: idlwave
;; This file is part of GNU Emacs.
;; Authors: JD Smith <jd.smith@utoledo.edu>
;; Carsten Dominik <dominik@astro.uva.nl>
;; Chris Chase <chase@att.com>
+;; Maintainer: emacs-devel@gnu.org
;; Keywords: processes
;; Package: idlwave
;; Copyright (C) 1999-2019 Free Software Foundation, Inc.
;; Author: Carsten Dominik <dominik@astro.uva.nl>
+;; Maintainer: emacs-devel@gnu.org
;; Keywords: processes
;; Package: idlwave
;; Authors: JD Smith <jd.smith@utoledo.edu>
;; Carsten Dominik <dominik@science.uva.nl>
;; Chris Chase <chase@att.com>
+;; Maintainer: emacs-devel@gnu.org
;; Version: 6.1.22
;; Keywords: languages
;; Inc.
;; Author: Hans Henrik Eriksen <hhe@ifi.uio.no>
+;; Maintainer: emacs-devel@gnu.org
;; Adapted-By: ESR
;; Keywords: languages