/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/ is in php-symfony-http-foundation 3.4.6+dfsg-1.
This file is owned by root:root, with mode 0o755.
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/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/AbstractSessionHandler.php
/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/MemcacheSessionHandler.php
/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/MemcachedSessionHandler.php
/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/MongoDbSessionHandler.php
/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/NativeFileSessionHandler.php
/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/NativeSessionHandler.php
/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/NullSessionHandler.php
/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php
/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/StrictSessionHandler.php
/usr/share/php/Symfony/Component/HttpFoundation/Session/Storage/Handler/WriteCheckSessionHandler.php