option('extension_set', type: 'combo', choices: ['classic', 'default', 'all'], value: 'default', description: 'Predefined sets of extensions' ) option('enable_extensions', type: 'array', value: [], description: 'Comma separated list of extensions to enable instead of a predefined set.' ) option('classic_mode', type: 'boolean', value: false, description: 'Enable installing data files for classic mode.' )