/usr/share/php/Symfony/Component/Serializer/Exception/ is in php-symfony-serializer 3.4.6+dfsg-1.
This file is owned by root:root, with mode 0o755.
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/usr/share/php/Symfony/Component/Serializer/Exception/BadMethodCallException.php
/usr/share/php/Symfony/Component/Serializer/Exception/CircularReferenceException.php
/usr/share/php/Symfony/Component/Serializer/Exception/ExceptionInterface.php
/usr/share/php/Symfony/Component/Serializer/Exception/ExtraAttributesException.php
/usr/share/php/Symfony/Component/Serializer/Exception/InvalidArgumentException.php
/usr/share/php/Symfony/Component/Serializer/Exception/LogicException.php
/usr/share/php/Symfony/Component/Serializer/Exception/MappingException.php
/usr/share/php/Symfony/Component/Serializer/Exception/NotEncodableValueException.php
/usr/share/php/Symfony/Component/Serializer/Exception/NotNormalizableValueException.php
/usr/share/php/Symfony/Component/Serializer/Exception/RuntimeException.php
/usr/share/php/Symfony/Component/Serializer/Exception/UnexpectedValueException.php
/usr/share/php/Symfony/Component/Serializer/Exception/UnsupportedException.php