The trace is kept for every element that has been validated. Validation shows that what was built meets the needs and requirements the stakeholders expressed, in other words that the right system was built, and the trace can be held in an RTM or a comparable information item.
This control maps to 1 controls across 1 other frameworks. If you already hold one of them, the evidence you collected for it is the starting point here rather than new work.
Every mapping shown was judged rather than inferred from wording similarity, and the ones that failed review are published too. See the coverage reports and what was rejected.
The graph holds this control, the 1 it maps to, and the evidence behind each claim, over MCP and REST.