This feature is applied internally to nodes that are on the other end of a relator association to indicate that the target node is related to the source node. This feature acts as a marker to tell Cloud CMS to consider the related nodes and the relator association at persistence time so the properties can be managed more efficiently in terms of mapping values from one end of the relationship to the other.
There is no need to apply or work with this feature manually.
For information on relator properties, please see relator properties.
This feature does require any configuration.