Dries Buytaert

Explanation

The Accept-CH header specifies HTTP Client Hints that the server requests from the client (typically a browser) to optimize content delivery.

• sec-ch-ua-arch: Requests the client's device CPU architecture, such as ARM or x86.
• sec-ch-ua-model: Requests the model of the client's device.
• sec-ch-ua-platform-version: Requests the version of the operating system the client is running.
• sec-ch-ua-full-version: Requests the complete version number of the client's browser.
• sec-ch-ua-full-version-list: Requests a detailed list of version numbers for the client's browser and its significant components.
• sec-ch-ua-bitness: Requests the bit architecture of the client's operating system, such as 32-bit or 64-bit.

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=2592000 specifies that the alternative service information is fresh for 2592000 seconds.

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

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 Strict-Transport-Security header (HSTS) instructs browsers to only use HTTPS for future connections to this domain, enhancing security by preventing downgrade attacks and cookie hijacking.
max-age specifies the time, in seconds, that the browser should remember to use HTTPS only for this domain.
includesubdomains instructs the browser that all subdomains are HTTPS-only as well.

The Via header tracks how a page is forwarded from proxy to proxy. Beware, not all proxies append themselves to the Via header.

The X-Content-Type-Options header, when set to nosniff, prevents MIME type sniffing. This enhances security by ensuring browsers respect the declared Content-Type of the response, mitigating MIME confusion attacks.
The value nosniff is correctly set, providing protection against MIME type sniffing attacks.

The size of the message body, in bytes.

missing Add a Content-Security-Policy header. The Content-Security-Policy header helps browsers prevent cross site scripting (XSS) and data injection attacks.

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-Frame-Options header. The X-Frame-Options header prevents this URL from being embedded in an iframe. This protects against clickjacking attacks. Alternatively, set a Content-Security-Policy header with a frame-ancestor directive.

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