TYPO3 Core

In older 7 versions packages like that were also stored in the packageState.php file:

 'symfony.yaml' => 
    array (
      'manifestPath' => 'Symfony/Component/Yaml/',
      'composerName' => 'symfony/yaml',
      'state' => 'inactive',
      'packagePath' => 'Packages/Libraries/symfony/yaml/',
      'classesPath' => 'Classes/',
      'suggestions' => 
      array (
      ),
    ),

which now Package to throw Exception\InvalidPackageManifestException
Unortunatelly PackageManager doesn't catch this exception, which result in Fatal error (probably error handler is not yet configured).