Original website: http://wmbiff.sourceforge.net/
WMBiff is an WindowMaker docking utility, that displays the number of read and unread messages in up to five mailboxes. You can also define actions to execute on new mail arrival (for example, play a sound file), [auto]fetchmail from a remote server or to execute your mail reader with a mouse click. WMBiff also supports notification of incoming Licq messages, so you can put Licq in the background.
At this moment, wmbiff supports unix-style, maildir, pop3, APOP, IMAP and IMAPS mailboxes, as well as Licq and GnomeICU history files.
For comments, see the original dockapps.org entry.
A newer version may be available in the Window Maker dockapps git repository:
git clone https://repo.or.cz/dockapps.git