I came across a broken link on https://getkirby.com/docs/cookbook/xmlsitemap in the “Demo” section.
Thanks for reporting, I’ve removed the link from the docs repo.
If you run a link-checker on https://getkirby.com/ or look in the access- or error-logs, you will find more internal dead links, I think.
Or add an internal reporting on the error page, that saves the referrer of the error page to a special log. This log will show these errors.
I always thought that was the whole idea behind broken link checkers