!!! Overview
[{$pagename}] are used to precisely describe the resource being fetched or the behavior of the server or the client. 

[{$pagename}] are defined in a [IANA Registry] [Message Headers|https://www.iana.org/assignments/message-headers/message-headers.xhtml|target='_blank']

[{$pagename}] may be one of the following:
* [HTTP Entity Header]
* [HTTP Request Header]
* [HTTP Response Header]

The [HTTP Method]/[HTTP Status Code] line and [HTTP Header Fields] [MUST] all end with <CR><LF> (that is, a carriage return followed by a line feed). The empty line must consist of only <CR><LF> and no other whitespace.

!! Field Order
The order in which [{$pagename}] with differing field names are received is not significant.

!! [HTTP Header Directives]
Some [{$pagename}]s have [HTTP Header Directive]s defined.

For [example] the "[Cache-Control]" [{$pagename}] is used to specify [HTTP Cache Directives] for [caches] along the request/response chain.

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]