This file is indexed.

/usr/share/doc/gnuchess-book/copyright is in gnuchess-book 1.02-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
This is the opening book of gnuchess. It used to be distributed
together with gnuchess up to version 5.02. The Debian package was
prepared by Lukas Geyer <lukas@debian.org>

Upstream location of the book is
ftp://ftp.gnu.org/pub/gnu/chess/book_1.02.pgn.gz

This opening book is in the public domain. It was put together and
cleaned up by Stuart Cracraft <cracraft@earthlink.net> and Simon
Waters <simon@wretched.demon.co.uk>. Stuart wrote the following in
email, when asked about copyright.

  I personally built the GNU Chess book from a large set of FREE
  game collections from the University of Pittsburgh chess server.
  These are NOT copyrighted and are PUBLIC. I also wrote the code
  for the GNU Chess book without any reference at all to any other
  author.

  It is GNU Chess code and PUBLIC book that is non-copyrightable.

  --Stuart

Note that all the code is in gnuchess, so this package itself is
purely public domain.

Lukas Geyer <lukas@debian.org>