+ * Modified username_extension masquerading to only use the
+ extended address on generated [Resent-]From: lines and SMTP
+ envelope From:. With Neil's original implementation, nmh's global
+ idea of the username was changed, which would result in inc lying
+ and saying you had no new mail because it was looking for a
+ mailbox called, for instance, "dan-nmh" (where username was "dan"
+ and $USERNAME_EXTENSION was "-nmh").
+