Hello, I see this exemple on Wikipedia, I want to know if HTTP Header comes in an index.html, in all HTML pages or in a separate file with a specific extension ? And how you know how to begin it, since it's going to be HTML5, and if there are must features or default features ? And if beginning with HTTP/1.1 200 OK will make my index.html be accepted in https://validator.w3.org/nu/#textarea ? Actually I'm trying to understand how this feature works and how should I know how to write it ?
(Source: Wikipedia, Hypertext Transfer Protocol)
HTTP/1.1 200 OK Date: Mon, 23 May 2005 22:38:34 GMT Content-Type: text/html; charset=UTF-8 Content-Length: 138 Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT Server: Apache/18.104.22.168 (Unix) (Red-Hat/Linux) ETag: "3f80f-1b6-3e1cb03b" Accept-Ranges: bytes Connection: close <html> <head> <title>An Example Page</title> </head> <body> Hello World, this is a very simple HTML document. </body> </html>