/usr/ is in php-horde-sessionhandler 2.2.7-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/
/usr/share/php/
/usr/share/php/Horde/
/usr/share/php/Horde/SessionHandler/
/usr/share/php/Horde/SessionHandler/Exception.php
/usr/share/php/Horde/SessionHandler/Storage/
/usr/share/php/Horde/SessionHandler/Storage/External.php
/usr/share/php/Horde/SessionHandler/Storage/Sql.php
/usr/share/php/Horde/SessionHandler/Storage/Memcache.php
/usr/share/php/Horde/SessionHandler/Storage/File.php
/usr/share/php/Horde/SessionHandler/Storage/Mongo.php
/usr/share/php/Horde/SessionHandler/Storage/Builtin.php
/usr/share/php/Horde/SessionHandler/Storage/Hashtable.php
/usr/share/php/Horde/SessionHandler/Storage/Stack.php
/usr/share/php/Horde/SessionHandler/Storage.php
/usr/share/php/Horde/SessionHandler.php
/usr/share/php/data/
/usr/share/php/data/Horde_SessionHandler/
/usr/share/php/data/Horde_SessionHandler/migration/
/usr/share/php/data/Horde_SessionHandler/migration/1_horde_sessionhandler_base_tables.php
/usr/share/php/data/Horde_SessionHandler/migration/2_horde_sessionhandler_fix_blob_length.php
/usr/share/php/.registry/
/usr/share/php/.registry/.channel.pear.horde.org/
/usr/share/php/.registry/.channel.pear.horde.org/horde_sessionhandler.reg
/usr/share/doc/
/usr/share/doc/php-horde-sessionhandler/
/usr/share/doc/php-horde-sessionhandler/copyright
/usr/share/doc/php-horde-sessionhandler/changelog.Debian.gz
/usr/share/doc/php-horde-sessionhandler/package.xml.gz