Will Baude, at Volokh, discusses a new novel about a law clerk who is asked by her judge not to reveal a jurisdictional defect. Baude uses 5.2 to analyze the issues. As I recall, the Federal Judicial Center discusses the ethics of clerking in a pamphlet (Maintaining the Public Trust) that assumes that clerks are governed as "judicial employees" under the The Code of Conduct for Judicial Employees and by other law specified at pp. 2-3 of the pamphlet. I suppose that both bodies of law could apply.
(The discussion brings to mind two kerfuffles about clerks and confidentiality: one about the book Closed Chambers and the other about the SCOTUS clerks who gave interviews about the Bush v. Gore decision to a journalist who published the story in Vanity Fair.
[edited after publishing to change "5.3" to "5.2," and to add the full name of the Code for judicial employees.]