XML tools should be able to validate the HTML locally, as these pages have already been "rendered" ahead of time. And it would be interesting to see some stats

XML tools should be able to validate the HTML locally, as these pages have already been "rendered" ahead of time. And it would be interesting to see some stats on the types of pages that are returned for the broken links. Are they returning HTTP 404s? 30x? 200's, or 500's? Does their site even allow for 300 redirection? But it makes sense to reduce infrastructure to serve static content, which are all points of failure anyway, or at least a maintenance burden.