What headers can reveal
Headers include status codes, redirect targets, cache behavior, content type, cookies, compression, CDN details and security policies. A header check can quickly reveal whether a page returns 200, redirects with 301 or 302, fails with 404, or is blocked by a server-side rule.
Security-related headers such as HSTS, Content-Security-Policy, X-Frame-Options and Referrer-Policy can reduce common web risks when configured correctly. Cache headers help explain why a browser or CDN keeps showing an older version of a page.