Normally, the main sitemap of TYPO3 is located only with ?type argument here: https://www.lumedis.de/?type=1533906435

This sitemap contains 2 "sub sitemap", one for each chunk of 1000 pages on your site. Your url is one of them directly.

If you have other extensions installed (like news), there are also sitemaps for these. So its never a good idea to check only one sitemap type.