/usr/share/php/Symfony/ is in php-symfony-polyfill-php70 1.2.0-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/Symfony/Polyfill/
/usr/share/php/Symfony/Polyfill/Php70/
/usr/share/php/Symfony/Polyfill/Php70/Php70.php
/usr/share/php/Symfony/Polyfill/Php70/Resources/
/usr/share/php/Symfony/Polyfill/Php70/Resources/stubs/
/usr/share/php/Symfony/Polyfill/Php70/Resources/stubs/ArithmeticError.php
/usr/share/php/Symfony/Polyfill/Php70/Resources/stubs/AssertionError.php
/usr/share/php/Symfony/Polyfill/Php70/Resources/stubs/DivisionByZeroError.php
/usr/share/php/Symfony/Polyfill/Php70/Resources/stubs/Error.php
/usr/share/php/Symfony/Polyfill/Php70/Resources/stubs/ParseError.php
/usr/share/php/Symfony/Polyfill/Php70/Resources/stubs/TypeError.php
/usr/share/php/Symfony/Polyfill/Php70/autoload.php
/usr/share/php/Symfony/Polyfill/Php70/bootstrap.php