Via the new "Tools > Create Google Sitemap" command you can now create the sitemap.xml file, based on the linked pages of the menu items.
A Google Sitemap allows you to inform search engine crawlers about URLs on your Web sites that are available for crawling. A Sitemap consists of a list of URLs and may also contain additional information about those URLs, such as when they were last modified, how frequently they change, etc.
You can find more information by clicking on the following URL:
https://www.google.com/webmasters/sitem