Protection from detriment and from breaches of confidentiality extends beyond the whistleblower to the other relevant interested parties that the held definition of detrimental conduct names (3.13): prospective whistleblowers and persons perceived to be whistleblowers, relatives and associates of a whistleblower, those who supported the whistleblower, and anyone involved in the whistleblowing process, which can include a legal entity; witnesses are among them, and 7.5.5 extends confidentiality to relevant interested parties. The measures of 8.3.2 and 8.4.2 (risk assessment, a documented set of measures, monitoring) apply to them as well. From the held definition and the quoted confidentiality clause; the clause text is not held.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.