WMMail.app is a "mail-checker" like xbiff.  It indicates the status of the
user's mailbox by showing animated XPM icons when incoming mails are
detected.  Additionally, it can be configured to execute a program on
incoming mail and/or on mouse double-clicks, and can provide a count of
emails in the user's mailbox.  It currently supports UNIX mbox files, MH
and MailDir mail folders, and IMAP4 remote mailboxes.

WMMail.app is based on asmail, a similar applet designed to work with the
Wharf of the AfterStep window manager.  However, WMMail.app has been
re-written to be compatible with the Window Maker Dock, i.e. WMMail.app
can be dragged and dropped on to (and off from) the Dock dynamically.