Template:Archive/doc

 is a context-sensitive archive message that works differently depending on whether it's used in namespaces   ,      or     . It cannot be displayed on this page, as it has no "default" condition, and does not address the template namespace at all.

Basically, it tells people that the talk page subpage or discussion thread has been archived. It then invites the user to go to the active discussion area relevant to that namespace in order to start a new discussion.