/usr/share/civicrm/settings/ is in civicrm-common 4.7.30+dfsg-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/civicrm/settings/Address.setting.php
/usr/share/civicrm/settings/Campaign.setting.php
/usr/share/civicrm/settings/Case.setting.php
/usr/share/civicrm/settings/Contribute.setting.php
/usr/share/civicrm/settings/Core.setting.php
/usr/share/civicrm/settings/Developer.setting.php
/usr/share/civicrm/settings/Directory.setting.php
/usr/share/civicrm/settings/Event.setting.php
/usr/share/civicrm/settings/Extension.setting.php
/usr/share/civicrm/settings/Localization.setting.php
/usr/share/civicrm/settings/Mailing.setting.php
/usr/share/civicrm/settings/Map.setting.php
/usr/share/civicrm/settings/Member.setting.php
/usr/share/civicrm/settings/Multisite.setting.php
/usr/share/civicrm/settings/Search.setting.php
/usr/share/civicrm/settings/Url.setting.php