For read operations: the original language code from the provider. For write operations: fallback value used when value is omitted or "unmapped_value". You must ensure this matches the provider's format.
LocalizationModelSourceValueUnion.CreateStr(/* values here */);LocalizationModelSourceValueUnion.CreateNumber(/* values here */);LocalizationModelSourceValueUnion.CreateBoolean(/* values here */);LocalizationModelSourceValueUnion.CreateLocalizationModelSourceValue(/* values here */);LocalizationModelSourceValueUnion.CreateArrayOfAny(/* values here */);