A computer system may generate a lineage graph for a data processing system. The lineage graph may contain one or more nodes, and it may identify the flow of data through the data processing system. The computer system may determine that a first node in the lineage graph defunct. The computer system may then generate a report for the data processing system and provide the report to a user. The report may include an explanation of why the first node is defunct. The computer system may insert an indication that the first node is defunct into metadata for the first node. The indication may also include the explanation of why the first node is defunct.