!!! Overview
[{$pagename}] is an [HTTP Entity Header] ([HTTP Header Field]) used to compress the [media-type]. When present, its value indicates what additional content [encoding] has been applied to the [HTTP Body]. 

[{$pagename}] lets the [client] know the [decoding] required in order to obtain the [media-type] referenced by the [Content-Type] header.

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