FormFileExtensionUpdate is broken because of new symfony expression language in TypoScript
FormFileExtensionUpdate wizard is broken because of the new symfony expression language in TypoScript.
FormFileExtensionUpdate make use of
\TYPO3\CMS\Form\Mvc\Configuration\ConfigurationManager::getTypoScriptSettings which calls the extbase configuration manager to resolve the TypoScript. This looks not ready for the usage in the install tool.
Not sure how to solve this issue without remove the usage of extbase, which maybe is the best solution.