/usr/share/civicrm/CRM/ACL/ is in civicrm-common 4.7.30+dfsg-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/civicrm/CRM/ACL/API.php
/usr/share/civicrm/CRM/ACL/BAO/
/usr/share/civicrm/CRM/ACL/BAO/ACL.php
/usr/share/civicrm/CRM/ACL/BAO/Cache.php
/usr/share/civicrm/CRM/ACL/BAO/EntityRole.php
/usr/share/civicrm/CRM/ACL/DAO/
/usr/share/civicrm/CRM/ACL/DAO/ACL.php
/usr/share/civicrm/CRM/ACL/DAO/Cache.php
/usr/share/civicrm/CRM/ACL/DAO/EntityRole.php
/usr/share/civicrm/CRM/ACL/Form/
/usr/share/civicrm/CRM/ACL/Form/ACL.php
/usr/share/civicrm/CRM/ACL/Form/ACLBasic.php
/usr/share/civicrm/CRM/ACL/Form/EntityRole.php
/usr/share/civicrm/CRM/ACL/Form/WordPress/
/usr/share/civicrm/CRM/ACL/Form/WordPress/Permissions.php
/usr/share/civicrm/CRM/ACL/Page/
/usr/share/civicrm/CRM/ACL/Page/ACL.php
/usr/share/civicrm/CRM/ACL/Page/ACLBasic.php
/usr/share/civicrm/CRM/ACL/Page/EntityRole.php