{
  "instance under 8 levels": (() => {
    // A class instance whose properties lie past the depth limit renders with
    // them elided, the same as any other value there.
    class Data {
      x = 1;
    }
    let value = new Data();
    for (let i = 0; i < 8; i++) {
      value = { d: value };
    }
    return value;
  })(),
}

--

instance under 8 levels:
{d:{d:{d:{d:{d:{d:{d:{d:/Data(...)}}}}}}}}
{
  d: {
    d: {
      d: {
        d: {
          d: {
            d: {
              d: {
                d: /Data(...)
              }
            }
          }
        }
      }
    }
  }
}
{
  d: {
    d: {
      d: {
        d: {
          d: {
            d: {
              d: {
                d: {
                  "/Data": {
                    "/...": "object"
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}