Ref # On Email?

Just a question on this, as I am working with IT to understand how WF stores this info.

On an email from WF, there is a REF# above the "See it In Workfront". What is that reference number, exactly? Does it give a precise reference to the notification? It doesn't tie to project ID, user ID, update ID, etc. 

Final question: if I am correct, is this stored anywhere in-system/is reportable, etc. Just mostly trying to figure out what value this number adds to either a user or to support. Thanks!