InstalledVersions::getRawData()

    public static function getRawData()
    {
        @trigger_error('getRawData only returns the first dataset loaded, which may not be what you expect. Use getAllRawData() instead which returns all datasets for all autoloaders present in the process.', E_USER_DEPRECATED);

        if (null === self::$installed) {
            // only require the installed.php file if this file is loaded from its dumped location,
            // and not from its source location in the composer/composer package, see https://github.com/composer/composer/issues/9937
            if (substr(__DIR__, -8, 1) !== 'C') {
                self::$installed = include __DIR__ . '/installed.php';
            } else {
                self::$installed = array();
            }
        }

        return self::$installed;
    }