Functional requirements come straight from investigative need and what users of the process expect; they state expected inputs and outputs, not how the process works, and the investigation is expected to meet every one of them (for example, having to read a particular filesystem type is functional because an evidence source brings that need).
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.