The following image illustrates that the second revision (B) at the plant level has been revised down into revision (C) in the sub configuration, and a link is created between those two. The revision (C) is also linked to the master design basis.
When a document is revised to a sub configuration, the icon from the higher configuration (plant) is updated to indicate that it also has a revision in a lower configuration (project). The ClaimedToConfigs property is set to the name of the lower configuration to which the revision was revised.