Fetch a domain's sitemap(s) and report their STRUCTURE — URL counts by path prefix — not their content. This is the fingerprint that separates a normal site from a programmatic content farm: a farm concentrates a huge majority of its URLs under one or two path prefixes (e.g. /best/-software/), while a normal site spreads them across many. Reads robots.txt Sitemap: directives first, falls back to /sitemap.xml then /sitemap_index.xml, follows one level of sitemap-index nesting, and handles gzipped .xml.gz files. Caps total URLs read (default 150,000) and always says when it capped, so a truncated read never looks like a small site. Returns found:false (not an error) when the domain has no sitemap. Example: sitemap_stats({ domain: "gitnux.org" })