As we all know, the sitemap.xml should contain no broken pages.
But happens with sitemaps that are created automatically by the system? There are thousands of links included there and I can't think any manual way to update the sitemap regularly.
So what is the standard for companies with huge sitemaps? How do they avoid the broken links from being added there or if they are already in the sitemap, how do they remove them (manually since like a very time-consuming task)?