[rules-users] Relation between Guvnor and Expert in Drools5.0

Hi All, Can you throw some light on Relation between Guvnor and Expert components in Drools5.0. Guvnor sounds like BRMS so does it have Rule engine ( or runtime) to execute rules ?. Is Expert module part of Guvnor ? If Guvnor doesn't have rule engine how does it excute rule when we do QA. I cannot find Expert module for down load. Is Rule engine runtime bunch of jars ( Drools-core.jar etc ) thanks Sumant