/usr/share/php/Symfony/Component/VarDumper/Caster/ is in php-symfony-var-dumper 2.7.10-0ubuntu2.
This file is owned by root:root, with mode 0o755.
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/usr/share/php/Symfony/Component/VarDumper/Caster/AmqpCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/Caster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/ConstStub.php
/usr/share/php/Symfony/Component/VarDumper/Caster/CutStub.php
/usr/share/php/Symfony/Component/VarDumper/Caster/DOMCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/DoctrineCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/ExceptionCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/MongoCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/PdoCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/ReflectionCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/ResourceCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/SplCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/StubCaster.php
/usr/share/php/Symfony/Component/VarDumper/Caster/XmlResourceCaster.php