For LEAP authentication, this optional parameter tells Radiator to convert the LEAP request into a conventional RADIUS-MSCHAP request. The new RADIUS-MSCHAP request is re-despatched to the Handlers, where it is detected and handled with <Handler ConvertedFromLEAP=1>.

This is useful for proxying LEAP requests to a remote RADIUS server that cannot handle LEAP, but which can handle RADIUS-MSCHAP. See goodies/eap_leap_proxy.cfg in your distribution for an example of how to configure such a convert and proxy system.