The tab is only available at model projects created during the generation of clustered audiences. For more details on this feature, please see the Standard Selection Rules documentation.
The tab allows you to view details of the how clusters exposed by the model are defined, in terms of the proportion of records therein that exhibit certain attribute values.
A View dropdown, displayed at the top left of the decision tree, allows you to choose the cluster you want to view.
A zoom control is provided to the top right.