[Enter description of this extension point.] The type of IndexEntry that should be managed. Must be null (or empty), if an index-entry-factory-type is specified. Usually, you defined index-entry-type instead (and leave this empty or null). But if you want to specify a custom factory, you can specify it here and leave index-entry-type undefined. [Enter the first release in which this extension point appears.] [Enter extension point usage example here.] [Enter API information here.] [Enter information about supplied implementation of this extension point.]