There are number of extension points for Views, DataLoaders/DataContainers that are not known to developers and can only be seen from "Generate Handlers" dialog. Usually this parameters named as subjects and targets and allow to bind some class method to be called as the delegate.
Ideally they all must be listed in documentation, but in fact only some of them really present. For instance try to find any information on "viewConfgirurer" target that allows to control EntityPicker dataset.