/panth-sitemap.xml is served by our controller via a url_rewrite row installed by Setup\Patch\Data\InstallSitemapRewrite. The core Magento_Sitemap module's filesystem-based sitemap is unaffected — ...

A complete XML sitemap replacement for Magento 2. One module runs the full pipeline — per-store sitemap profiles, seven entity-type contributors (product, category, CMS, landing page, blog, video, ...