null:org.apache.solr.common.SolrException: Error loading class 'org.apache.solr.response.transform.EditorialMarkerFactory'

Hi,
I can't seem to get the doc transformer to work.
I'm turned on the elevated query component and I tried to turn on the doc transformer in the solrconfig.xml file to get [elevated] appear in the results.
I tried both of these separately and I got the same error and the core would not load:

<transformer name="qecBooster" class="org.apache.solr.response.transform.EditorialMarkerFactory" />
<transformer name="elevated" class="org.apache.solr.response.transform.EditorialMarkerFactory" />

Please advise...