Message number is the message's unique number in the folder. In the NNTP folder, it is article number, in the IMAP folder, it is UID and in the MH folder, it is the filename of the message. Temporal mark and Persistent mark are described later. Sender 's indentation corresponds to the depth of the thread. Sender name is displayed as nickname if it is defined in the address book.
Temporary marks indicates message operations.
After you type o key, prompt appears to input refile destination. Your answer is printed in the summary line. You can put this mark by typing O key. The difference between this mark and refile mark is, this mark does not delete the message while latter does. The persistent mark indicates the message's status and it is saved.