Explain each attribute in this Set-Cookie header.

Each attribute sets one rule for the cookie:

• sid=8f2k1 is the cookie's name and value.
• HttpOnly hides the cookie from JavaScript. document.cookie cannot read it. This limits damage from XSS (cross-site scripting: an attacker's script running on your page), because the script cannot steal the cookie.
• Secure means the browser only sends the cookie over HTTPS.
• SameSite=Lax controls when the cookie goes with requests from other sites. Details below.
• Path=/ makes the cookie apply to every path on the host.
• Max-Age=3600 makes it a persistent cookie that expires in one hour (3600 seconds).

SameSite=Lax in detail. The browser sends the cookie:

• with same-site requests.
• with top-level GET navigations from other sites, like clicking a link to your site.

It does not send it with cross-site subrequests (images, iframes, fetch calls) or cross-site POSTs.

Max-Age in detail. Without Max-Age or Expires, it would be a session cookie. The browser removes a session cookie when the browser session ends. If both Max-Age and Expires are set, Max-Age wins.

There is no Domain attribute. So the cookie is host-only: the browser sends it only to the exact host that set it, not to subdomains.