The files in this directory are used to generate stock_strings.dart, which contains the StockStrings class. This localizations class is used by the stocks application to look up localized message strings. The stocks app uses the Dart intl package.
To update the English and Spanish localizations, modify the stocks_en_US.arb, stocks_en.arb, or stocks_es.arb files. See the ARB specification for more info.
To modify the project's configuration of the localizations tool, change the l10n.yaml file.
The StockStrings class creates a delegate that performs message lookups based on the locale of the device. In this case, the stocks app supports en, en_US, and es locales. Thus, the StockStringsEn and StockStringsEs classes extends StockStrings. StockStringsEnUs extends StockStringsEn. This allows StockStringsEnUs to fall back on messages in StockStringsEn.