Sitemap Topics Route

Topic hub URLs (largest graph topics, bounded). When the graph is unavailable the urlset is empty-but-valid — the index simply omits the child rather than 500ing — unless this process served the layer within the last 15 minutes, in which case that list is served stale (marked X-Served-From: last-known-good, edge-capped at 5 min): an empty urlset tells every crawler to drop the whole family, so a blip must not erase what the graph itself just advertised.