!!! Overview
[{$pagename}] Code hash value. 

[{$pagename}] value is the [base64url] [encoding] of the left-most half of the hash of the octets of the [ASCII] representation of the [code|authorization Code] value, where the [hash] algorithm used is the [hash] algorithm used in the [alg] Header Parameter of the [id_token]'s [JOSE] Header. For instance, if the [alg] is [HS512], [hash] the [code|authorization Code] value with [SHA-512], then take the left-most 256 [bits] and [base64url] [encode] them. 

The [{$pagename}] value is a [case-sensitive] [string]. 

If the [id_token] is issued from the [Authorization_endpoint] with a [code|authorization Code], which is the case for the [response_type] values code [id_token] and [code|authorization Code] [id_token] [token], this is [REQUIRED]; otherwise, its inclusion is [OPTIONAL].

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