To get to this page, go to Settings → Message Archiving → Search, search for messages, then click on the search results to go to the Results tab

This page shows the results of an archive search. Up to 1000 results are displayed. You can select messages (use shift-click & ctrl-click to select multiple messages) and copy them to a VPOP3 user using the Copy Messages To option above the results list.

If you double-click on a message in the results list then you will be shown the raw message content, as well as some extra information, such as the IP address it came from (if it was received by SMTP), the authenticated sender (if any), any attachments, and so on. You will also be given a list of other messages in the same conversation (thread) which you can view. From this window you can also copy the message or entire thread to a specified user.