#1203699034: A cache with identifier "extbase_object" does not exist.

Die Lösung:
In der LocalConfiguration.php muss unter ['SYS']['caching']['cacheConfigurations'] folgendes ergänzt werden:

'extbase_object' => [
    'backend' => 'TYPO3\\CMS\\Core\\Cache\\Backend\\Typo3DatabaseBackend',
    'frontend' => 'TYPO3\\CMS\\Core\\Cache\\Frontend\\VariableFrontend',
    'groups' => [
        'system',
    ],
    'options' => [
        'defaultLifetime' => 0,
    ],
 ],