Discoverability · 30 points
sitemap.xml
One check, stated three ways: what we measure, what would make it wrong, and how to confirm it yourself.
What this measures
Whether /sitemap.xml or /sitemap_index.xml returns readable XML, including a sitemap declared in robots.txt at a non-standard path.
Where this check can be wrong
A sitemap can be perfectly served and still months stale; we read the file, we do not compare it against your real route count. Absence from it proves nothing on its own.
Verify it without taking our word for it
curl -s https://your.site/sitemap.xml | head -20, then grep the max <lastmod> date and ask whether it matches your last deploy.