Dries Buytaert

Explanation

The date and time at which the request was made. A browser uses it for age calculations rather than using its own internal date and time; e.g. when comparing against Max-Age or Expires.

The type of the message body, specified as a MIME type.

The cf-ray header provides a unique identifier for each request through Cloudflare. It's useful for troubleshooting and tracking requests in Cloudflare logs.

The page was served from Cloudflare's cache.

The time in seconds that the page has been in the shared proxy cache. The maximum age is set by max-age or s-maxage in the Cache-Control header.

The date and time at which the origin server believes the page was last modified.

The Content Security Policy (CSP) header helps prevent cross-site scripting (XSS), clickjacking, and other code injection attacks by specifying which dynamic resources are allowed to load.
frame-ancestors defines what parents may embed a page using <frame>, <iframe>, <object>, <embed> or <applet>.
Notice Consider adding the upgrade-insecure-requests directive to automatically upgrade HTTP requests to HTTPS, helping to prevent mixed content issues.

The Vary header specifies a list of headers that must be considered when caching responses. For a cached response to be used, these headers must match between the cached response and the new request. This ensures that the appropriate version of a resource is served based on factors like language, encoding, or device type.

A cookie that was sent from the server to the browser.
domain= sets the domain to which the cookie will be sent.
path= indicates the path that must exist in the requested URL for the browser to send the cookie.
Warning samesite=none instructs the browser to send the cookie to all cross-site requests, such as on requests to load images or frames from other sites. This enables third-party sites to log cookie data. This could lead to data leaks and cross-site request forgery attacks. To improve security, set to samesite=strict or samesite=lax.
secure instructs the browser to only send the cookie back when HTTPS requests are used, making it more resistant to man-in-the-middle attacks.
httponly forbids JavaScript from accessing the cookie. Helps mitigate the risk of client side scripts accessing a protected cookie.

The alt-svc header advertises alternative services for accessing the same resource, enabling protocol negotiation and potential performance improvements.
h3 indicates that HTTP/3 is supported. Variants like h3-29 refer to specific drafts of the HTTP/3 protocol.
ma=86400 specifies that the alternative service information is fresh for 86400 seconds.

missing Add a Strict-Transport-Security header. The Strict-Transport-Security header or HSTS header is used to instruct browsers to only use HTTPS, instead of using HTTP. It helps enforce secure communication.

missing Add a Referrer-Policy header. When a visitor navigates from one page to another, browsers often pass along referrer information. The Referrer-Policy header controls how much referrer information a browser can share. This is important to configure when private information is embedded in the path or query string and passed onto an external destination.

missing Add a Permissions-Policy header. Restrict access to device features like the camera, microphone, location, accelerometer and much more.

missing Add a Cross-Origin-Embedder-Policy to specify how this page can be loaded by cross-origin resources.

missing Add a Cross-Origin-Opener-Policy header to opt-in into better browser isolation.

missing Add a Cross-Origin-Resource-Policy header to specify who can load this page.

missing Add a X-Permitted-Cross-Domain-Policies header to prevent Flash, Adobe Reader and other clients from sharing data across domains.