untranslated-messages-file

The location of a file that describes the localization messages haven’t been translated yet. Using this option creates a JSON file at the target location, in the following format:  "locale": ["message_1", "message_2" ... "message_n"] If this option is not specified, a summary of the messages that haven’t been translated are printed on the command line.

output-class

The Dart class name to use for the output localization and localizations delegate classes. The default is AppLocalizations.

preferred-supported-locales

The list of preferred supported locales for the application. By default, the tool generates the supported locales list in alphabetical order. Use this flag to default to a different locale.For example, pass in [ en_US ] to default to American English if a device supports it.

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