/usr/share/php/Horde/ is in php-horde-smtp 1.9.2-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/Horde/Smtp/
/usr/share/php/Horde/Smtp.php
/usr/share/php/Horde/Smtp/Connection.php
/usr/share/php/Horde/Smtp/Debug.php
/usr/share/php/Horde/Smtp/Exception/
/usr/share/php/Horde/Smtp/Exception.php
/usr/share/php/Horde/Smtp/Exception/Recipients.php
/usr/share/php/Horde/Smtp/Filter/
/usr/share/php/Horde/Smtp/Filter/Body.php
/usr/share/php/Horde/Smtp/Filter/Data.php
/usr/share/php/Horde/Smtp/Lmtp.php
/usr/share/php/Horde/Smtp/Password/
/usr/share/php/Horde/Smtp/Password.php
/usr/share/php/Horde/Smtp/Password/Xoauth2.php
/usr/share/php/Horde/Smtp/Translation.php