I just tried to install the extension via composer. Some things I noticed: 1) Version 1.0.2 was installed and not 1.1.0 (which seems to be available since july 2022 and was TYPO3 11 compatible) https://github.com/web-vision/wv_file_cleanup/commit/a902c324c159c7a849c98e9bb187f47e2a020703 2) Because of that, the extension key warning was shown because the extension key does not exists in version 1.0.2: The TYPO3 extension package "web-vision/wv_file_cleanup", does not define an extension key in its composer.json. Please report this to the author of this package. Specifying the extension key will be mandatory in future versions of TYPO3 (see: https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/ExtensionArchitecture/FileStructure/ComposerJson.html#extra) This also breaks the TYPO3 installation:  Also, the newer version is not available here: https://packagist.org/packages/web-vision/wv_file_cleanup TYPO3 11.5.30