/etc/nagios3/stylesheets/history.css is in nagios3-cgi 3.5.1.dfsg-2.1ubuntu1.3.
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 | /* exfoliation: a nagios makeover */
/* Copyright 2010 Matthew Wall, all rights reserved */
/* */
/* Permission to use, copy, modify, and distribute this software for any */
/* purpose with or without fee is hereby granted, provided that the above */
/* copyright notice and this permission notice appear in all copies. */
.history { }
|