final String xpath = xpathConfigMap.get(XPath.DEFAULT_LANG);
        if (StringUtil.isNotBlank(xpath)) {
            return xpath;
        }
        return fessConfig.getCrawlerDocumentHtmlLangXpath();
    }

    /**
     * Gets the XPath expression for extracting content.
     *
     * @param fessConfig the Fess configuration
     * @param xpathConfigMap the XPath configuration map

     * comment: XPath to extract language attribute from HTML documents.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getCrawlerDocumentHtmlLangXpath();

    /**
     * Get the value for the key 'crawler.document.html.digest.xpath'. <br>
     * The value is, e.g. //META[@name='description']/@content <br>