Symfony version(s) affected: 5.0.1

Description
Issuing ../bin/console config:dump-reference --format=xml FrameworkBundle gives out error:

In ArrayNode.php line 146:
[TypeError]
Argument 1 passed to Symfony\Component\Config\Definition\ArrayNode::setName() must be of >the type string, null given, called in /home/artur/dev/git/php/sym1/vendor/symfony/config/Definition/Dumper/XmlReferenceDumper.php on line 94 `

How to reproduce

1. Install symfony binary
2. Issue symfony new --full ./
3. Issue ../bin/console config:dump-reference --format=xml FrameworkBundle

Additional context
Dumping XML config reference for components other than FrameworkBundle works as expected.
My PHP is:

PHP

---

Version 7.3.10-1+b1
Architecture 64 bits
Intl locale en_US
Timezone Europe/Berlin (2019-12-05T20:04:36+01:00)
OPcache true
APCu false
Xdebug false