The Index file contains links to each of the other files that the Sitemap Generator produces.

For example:

<?xml version="1.0" encoding="UTF-8" ?> 
  <sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <sitemap>
    <loc>http://localhost:8006/discover/detail0.xml</loc> 
  </sitemap>
  <sitemap>
    <loc>http://localhost:8006/discover/navigation0.xml</loc> 
  </sitemap>
  <sitemap>
    <loc>http://localhost:8006/discover/searchterm0.xml</loc> 
  </sitemap>
  <sitemap>
    <loc>http://localhost:8006/discover/staticpage0.xml</loc> 
  </sitemap>
</sitemapindex>