Flarum\Locale\LocaleServiceProvider::register PHP Method

    public function register()
    {
        $this->app->singleton('Flarum\\Locale\\LocaleManager');
        $this->app->alias('Flarum\\Locale\\LocaleManager', 'flarum.localeManager');
        $this->app->singleton('translator', function () {
            $defaultLocale = $this->getDefaultLocale();
            $translator = new Translator($defaultLocale, new MessageSelector());
            $translator->setFallbackLocales([$defaultLocale, 'en']);
            $translator->addLoader('prefixed_yaml', new PrefixedYamlFileLoader());
            return $translator;
        });
        $this->app->alias('translator', 'Symfony\\Component\\Translation\\Translator');
        $this->app->alias('translator', 'Symfony\\Component\\Translation\\TranslatorInterface');
    }