/usr/share/php/ is in php-horde-mail 2.4.0-4.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/Horde/Mail/Transport/Smtphorde.php
/usr/share/php/.registry/
/usr/share/php/.registry/.channel.pear.horde.org/
/usr/share/php/.registry/.channel.pear.horde.org/horde_mail.reg
/usr/share/php/Horde/
/usr/share/php/Horde/Mail/
/usr/share/php/Horde/Mail/Exception.php
/usr/share/php/Horde/Mail/Rfc822.php
/usr/share/php/Horde/Mail/Rfc822/
/usr/share/php/Horde/Mail/Rfc822/Object.php
/usr/share/php/Horde/Mail/Rfc822/Identification.php
/usr/share/php/Horde/Mail/Rfc822/GroupList.php
/usr/share/php/Horde/Mail/Rfc822/Address.php
/usr/share/php/Horde/Mail/Rfc822/List.php
/usr/share/php/Horde/Mail/Rfc822/Group.php
/usr/share/php/Horde/Mail/Transport/
/usr/share/php/Horde/Mail/Transport/Smtp.php
/usr/share/php/Horde/Mail/Transport/Null.php
/usr/share/php/Horde/Mail/Transport/Sendmail.php
/usr/share/php/Horde/Mail/Transport/Mail.php
/usr/share/php/Horde/Mail/Transport/Smtpmx.php
/usr/share/php/Horde/Mail/Transport/Mock.php
/usr/share/php/Horde/Mail/Transport/Lmtphorde.php
/usr/share/php/Horde/Mail/Transport.php