/usr/share/php/Icinga/Protocol/ is in php-icinga 2.1.0-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/Icinga/Protocol/Dns.php
/usr/share/php/Icinga/Protocol/File/
/usr/share/php/Icinga/Protocol/File/Exception/
/usr/share/php/Icinga/Protocol/File/Exception/FileReaderException.php
/usr/share/php/Icinga/Protocol/File/FileIterator.php
/usr/share/php/Icinga/Protocol/File/FileQuery.php
/usr/share/php/Icinga/Protocol/File/FileReader.php
/usr/share/php/Icinga/Protocol/File/LogFileIterator.php
/usr/share/php/Icinga/Protocol/Ldap/
/usr/share/php/Icinga/Protocol/Ldap/Discovery.php
/usr/share/php/Icinga/Protocol/Ldap/LdapCapabilities.php
/usr/share/php/Icinga/Protocol/Ldap/LdapConnection.php
/usr/share/php/Icinga/Protocol/Ldap/LdapException.php
/usr/share/php/Icinga/Protocol/Ldap/LdapQuery.php
/usr/share/php/Icinga/Protocol/Ldap/LdapUtils.php
/usr/share/php/Icinga/Protocol/Ldap/Node.php
/usr/share/php/Icinga/Protocol/Ldap/Root.php
/usr/share/php/Icinga/Protocol/Livestatus/
/usr/share/php/Icinga/Protocol/Livestatus/Connection.php
/usr/share/php/Icinga/Protocol/Livestatus/Query.php
/usr/share/php/Icinga/Protocol/Livestatus/ResponseRow.php
/usr/share/php/Icinga/Protocol/Nrpe/
/usr/share/php/Icinga/Protocol/Nrpe/Connection.php
/usr/share/php/Icinga/Protocol/Nrpe/Packet.php