/usr/share/php/Symfony/Component/Security/Csrf/ is in php-symfony-security 2.7.10-0ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/Symfony/Component/Security/Csrf/CsrfToken.php
/usr/share/php/Symfony/Component/Security/Csrf/CsrfTokenManager.php
/usr/share/php/Symfony/Component/Security/Csrf/CsrfTokenManagerInterface.php
/usr/share/php/Symfony/Component/Security/Csrf/Exception/
/usr/share/php/Symfony/Component/Security/Csrf/Exception/TokenNotFoundException.php
/usr/share/php/Symfony/Component/Security/Csrf/TokenGenerator/
/usr/share/php/Symfony/Component/Security/Csrf/TokenGenerator/TokenGeneratorInterface.php
/usr/share/php/Symfony/Component/Security/Csrf/TokenGenerator/UriSafeTokenGenerator.php
/usr/share/php/Symfony/Component/Security/Csrf/TokenStorage/
/usr/share/php/Symfony/Component/Security/Csrf/TokenStorage/NativeSessionTokenStorage.php
/usr/share/php/Symfony/Component/Security/Csrf/TokenStorage/SessionTokenStorage.php
/usr/share/php/Symfony/Component/Security/Csrf/TokenStorage/TokenStorageInterface.php