What's the rationale behind the HTTP Date header?

Question

I have read RFC 2616, but still I wonder, what the Date field is for. There is the Last-Modified field, that actually has a meaning besides just serving metadata, that is, f

Answer 1

Please consider not to use the Date Header as it is on the list of the "Forbidden header names".

The following description from the MDN web docs might help:

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A forbidden header name is the name of any HTTP header that cannot be modified programmatically; specifically, an HTTP request header name (in contrast with a Forbidden response header name).

Modifying such headers is forbidden because the user agent retains full control over them. Names starting with Sec- are reserved for creating new headers safe from APIs using Fetch that grant developers control over headers, such as XMLHttpRequest.

Forbidden header names start with Proxy- or Sec-, or are one of the following names:

• Accept-Charset
• List item
• Accept-Encoding
• Access-Control-Request-Headers
• Access-Control-Request-Method
• Connection
• Content-Length
• Cookie
• Cookie2
• Date
• DNT
• Expect
• Host
• Keep-Alive
• Origin
• Proxy-
• Sec-
• Referer
• TE
• Trailer
• Transfer-Encoding
• Upgrade
• Via