How does locale get reported?

Does it normalise the locale between supported locales and used local?

by David Storey

JavaScript

var locale = "en-ZZ",
    supported = Intl.DateTimeFormat.supportedLocalesOf(locale),
    dateFormat = Intl.DateTimeFormat(locale);

console.clear();
console.log("supported: " + supported[0]);
console.log("used: " + dateFormat.resolvedOptions().locale);