Copyright for ptrace.2:

Copyright (c) 1993 Michael Haardt <michael@moria.de>
Fri Apr  2 11:32:09 MET DST 1993

and changes Copyright (C) 1999 Mike Coleman (mkc@acm.org)
-- major revision to fully document ptrace semantics per recent Linux
   kernel (2.2.10) and glibc (2.1.2)
Sun Nov  7 03:18:35 CST 1999

and Copyright (c) 2011, Denys Vlasenko <vda.linux@googlemail.com>
and Copyright (c) 2015, 2016, Michael Kerrisk <mtk.manpages@gmail.com>

License for ptrace.2:

This is free documentation; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.

The GNU General Public License's references to "object code"
and "executables" are to be interpreted as the output of any
document formatting or typesetting system, including
intermediate and printed output.

This manual is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public
License along with this manual; if not, see
<http://www.gnu.org/licenses/>.