in locales-common/src/main/java/com/spotify/i18n/locales/common/model/SupportedLocale.java [126:137]
private static SupportedLocale fromValidatedULocale(final ULocale validatedULocale) {
ULocale rootLocaleForFormatting =
LocalesHierarchyUtils.getHighestAncestorLocale(validatedULocale);
return SupportedLocale.builder()
.localeForTranslations(validatedULocale)
.relatedLocalesForFormatting(
Stream.concat(
Stream.of(rootLocaleForFormatting),
LocalesHierarchyUtils.getDescendantLocales(rootLocaleForFormatting).stream())
.collect(Collectors.toSet()))
.build();
}