It defines the subframe definitions for the navigational links and the message data. The following derived file defines the navigational links for a message. The links will be displayed in a frame above the converted message. The thread index is setup where a thread will have the subject in bold at the top of the thread and the names of the authors of the messages in the thread will be hyperlinked to the actual message. Nested unordered lists are used to provide a visual cue of the depths of the thread.
Unique messages are show in normal text.
Before the thread list, we will have links to the date index, previous page, first page, last page, and next page. I.e. it does not start a thread or is part of a thread. This resource is only meant to provide some informative cue for the reader. Notice, no links are defined in the resource. It is used to restart a thread that has been split by a page boundary.