Last usage allows you to use protocol specification
http://www.icewarp.com* -> https://www.icewarp.com*
E.g. http://icewarp.com/secure/* -> https://icewarp.com/secure/*
So if a plain HTTP connection would be made to the /secure/ URI it would be redirected to HTTPS to the same directory. It also works vice versa. From https:// to http://
All combinations of these can be used for non regex Rewrite. Anything you want. I'm not aware of any other server that has this functionality.