A map containing <locale, message> pairs, where locale is a well-formed BCP 47 language code, such as en-US, es-ES, or fr.
An object containing a list of "key": value pairs. Example: { "name": "wrench", "mass": "1.3kg", "count": "3" }.
defaultMessage
string
The default message displayed if no localized message is specified or the user's locale doesn't match with any of the localized messages. A default message must be provided if any localized messages are provided.