!!! Overview[1]
[{$pagename}] is a [HTTP Method] which requests that the enclosed entity be stored under the supplied [URI]. 

If the [URI] refers to an already existing resource, it is modified.

If the URI does not point to an existing resource, then the server can create the resource with that [URI].

The difference between [{$pagename}] and [HTTP POST] is that [{$pagename}] is [Idempotent] where successive identical [HTTP POST] may have additional effects, like passing an order several times.


!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
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* [#1] - [Request methods|Wikipedia:Hypertext_Transfer_Protocol#Request_methods|target='_blank'] - based on information obtained 2016-05-21- 
* [#2] - [POST|https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/POST|target='_blank'] - based on information obtained 2020-04-19