The copyright information (listed in doc/kerbman.texinfo) is as follows.

CNS includes man pages and software developed at the Massachusetts
Institute of Technology, which includes this copyright information:

Copyright @copyright{} 1989 by the Massachusetts Institute of Technology
 
Export of software employing encryption from the United States of
America is assumed to require a specific license from the United
States Government.  It is the responsibility of any person or
organization contemplating export to obtain such a license before
exporting.
 
WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
distribute this software and its documentation for any purpose and
without fee is hereby granted, provided that the above copyright
notice appear in all copies and that both that copyright notice and
this permission notice appear in supporting documentation, and that
the name of M.I.T. not be used in advertising or publicity pertaining
to distribution of the software without specific, written prior
permission.  M.I.T. makes no representations about the suitability of
this software for any purpose.  It is provided ``as is'' without express
or implied warranty.

Copyright @copyright{} 1991, 1992, 1994, 1995 Cygnus Support

Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission 
notice are preserved on all copies.

Permission is granted to process this file through TeX and print the
results, provided the printed document carries a copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that
the entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions.