I think the OP is asking to have the link to the exception list to request to ADD challenge caches, (and added particularly those that do not have the word challenge in their title - which are mainly the older ones.)
@TerraViators - There isnt a link, as only moderators and a few others have access - so please list any challenge caches that you think need adding, here, and they will be added to the list - if they are not already on that list