/usr/share/zentyal/stubs/ is in zentyal-squid 2.3.11+quantal1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/zentyal/stubs/squid/
/usr/share/zentyal/stubs/squid/adzapper.conf.mas
/usr/share/zentyal/stubs/squid/bannedextensionlist.mas
/usr/share/zentyal/stubs/squid/bannedmimetypelist.mas
/usr/share/zentyal/stubs/squid/bannedphraselist.mas
/usr/share/zentyal/stubs/squid/bannedregexpurllist.mas
/usr/share/zentyal/stubs/squid/bannedsitelist.mas
/usr/share/zentyal/stubs/squid/bannedurllist.mas
/usr/share/zentyal/stubs/squid/clamdscan.conf.mas
/usr/share/zentyal/stubs/squid/dansguardian.conf.mas
/usr/share/zentyal/stubs/squid/dansguardian.logrotate
/usr/share/zentyal/stubs/squid/dansguardianfN.conf.mas
/usr/share/zentyal/stubs/squid/exceptionphraselist.mas
/usr/share/zentyal/stubs/squid/exceptionsitelist.mas
/usr/share/zentyal/stubs/squid/exceptionurllist.mas
/usr/share/zentyal/stubs/squid/filtergroupslist.mas
/usr/share/zentyal/stubs/squid/greysitelist.mas
/usr/share/zentyal/stubs/squid/greyurllist.mas
/usr/share/zentyal/stubs/squid/ipgroups.mas
/usr/share/zentyal/stubs/squid/pics.mas
/usr/share/zentyal/stubs/squid/squid.conf.mas
/usr/share/zentyal/stubs/squid/template.html.mas
/usr/share/zentyal/stubs/squid/zentyal-squid.cron.mas