Core_Command::get_download_url PHP Method

    private function get_download_url($version, $locale = 'en_US', $file_type = 'zip')
    {
        if ('nightly' === $version) {
            if ('zip' === $file_type) {
                return 'https://wordpress.org/nightly-builds/wordpress-latest.zip';
            } else {
                WP_CLI::error('Nightly builds are only available in .zip format.');
            }
        }
        if ('en_US' === $locale) {
            $url = 'https://wordpress.org/wordpress-' . $version . '.' . $file_type;
            return $url;
        } else {
            $url = sprintf('https://%s.wordpress.org/wordpress-%s-%s.' . $file_type, substr($locale, 0, 2), $version, $locale);
            return $url;
        }
    }