!!! Overview
[{$pagename}] refers to supplemental [data] placed at the beginning of a [block] or a [packet] or a [Datagram] of [Data At Rest] or [Data In Transit]. 


In [data] [Communication], the [data] following the [{$pagename}] are sometimes called the [payload] or body.

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
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* [#1] - [Header_(computing)|Wikipedia:Header_(computing)|target='_blank'] - based on information obtained 2018-03-25-