assertEscaping(xmlEscaper, "\uFFFD", '\uFFFF');

    assertEquals(
        "0xFFFE is forbidden and should be replaced during escaping",
        "[\uFFFD]",
        xmlEscaper.escape("[\ufffe]"));
    assertEquals(
        "0xFFFF is forbidden and should be replaced during escaping",
        "[\uFFFD]",
        xmlEscaper.escape("[\uffff]"));
  }

- Added support for CEL expressions with escaped names in the structured authentication config. Using `[...]` to access claims or user data was recommended when names contained characters that would otherwise need escaping. CEL optionals with `?` could be used where has was not applicable — for example, `claims[?"kubernetes.io"]` or `user.extra[?"domain.io/foo"]`. ([#131574](https://github.com/kubernetes/kubernetes/pull/131574), [@enj](https://github.com/enj)) [SIG...