/usr/share/mysql/ is in mariadb-server-10.1 10.1.26-0+deb9u1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/mysql/debian-start.inc.sh
/usr/share/mysql/echo_stderr
/usr/share/mysql/errmsg-utf8.txt
/usr/share/mysql/fill_help_tables.sql
/usr/share/mysql/maria_add_gis_sp.sql
/usr/share/mysql/maria_add_gis_sp_bootstrap.sql
/usr/share/mysql/mysql_performance_tables.sql
/usr/share/mysql/mysql_system_tables.sql
/usr/share/mysql/mysql_system_tables_data.sql
/usr/share/mysql/mysql_test_data_timezone.sql
/usr/share/mysql/policy/
/usr/share/mysql/policy/apparmor/
/usr/share/mysql/policy/apparmor/README
/usr/share/mysql/policy/apparmor/usr.sbin.mysqld
/usr/share/mysql/policy/apparmor/usr.sbin.mysqld.local
/usr/share/mysql/policy/selinux/
/usr/share/mysql/policy/selinux/README
/usr/share/mysql/policy/selinux/mariadb-server.fc
/usr/share/mysql/policy/selinux/mariadb-server.te
/usr/share/mysql/wsrep_notify