A controller whose purposes do not, or no longer, require identifying the data subject need not keep or acquire extra information only to comply with the Regulation. Where it can show it cannot identify the data subject it must, if possible, tell the data subject, and Articles 15 to 20 then apply only if the data subject supplies information enabling identification.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.