The most third party extension and service providers can work with the XML link SchuWeb Sitemap is providing in the backend. Please see SchuWeb Sitemap Quickstart how to get the link.
Some third party extension or service providers require a sitemap.xml file. Thanks to sshcli we have now a htaccess RewriteRule to redirect <YourDomain>/sitemap.xml to the XML link from SchuWeb Sitemap.
Insert this code snippet into your htaccess file, but don't do this if you don't know how to edit you htaccess file!
RewriteRule ^sitemap\.xml$ /index.php?option=com_schuweb_sitemap&view=xml&tmpl=component&id=1 [L]
More information about htaccess files and Joomla! https://docs.joomla.org/Preconfigured_htaccess