MAP extension in LW

Lispworks has extended some sequence functions like CONCATENATE and MAP:
<lib/5-1-0-0/manual/online/web/LWRM/html/lwref-94.htm#marker-1039891>
,----
|  map result-type  function  &rest sequences  => result
|
| The map function has been extended to take any Common Lisp type. The
| result will be of type result-type unless this is not possible, in
| which case a type-error is signalled.
`----

Can I have an example that illustrates where (and how) this is being
used?

Thanks,
--
Madhu