!!! Overview
[{$pagename}] added in [X509v2] to handle the possible reuse of [Certificate Subject] and/or [Certificate Issuer] names over time.  Their use is [deprecated] by the [IETF], so you shouldn't generate these in your [certificates]. 

If you're writing [certificate]-handling code, just treat them as a blob which happens to be an encoded [bitstring].

%%prettify 
{{{
UniqueIdentifier ::= BITSTRING
}}} /%

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