Ah, thanks for this! I was going to ask if someone could run `strings` on the binary.

I get back:

  {
    "version": 1,
    "urls": {
      "small_https_download_url": "https://mensura.cdn-apple.com/api/v1/gm/small",
      "large_https_download_url": "https://mensura.cdn-apple.com/api/v1/gm/large",
      "https_upload_url": "https://mensura.cdn-apple.com/api/v1/gm/slurp"
    },
    "test_endpoint": "ausyd2-edge-bx-006.aaplimg.com"
  }

I can't pinpoint the semantic value of `test_endpoint`. However,

- .../small gives me 0 bytes

- .../large gives me 4 gigabytes (!!) which I presume I am expected to range-request parts of

- .../slurp accepts input and gives me some stats back.

Upload tests are simple:

  $ head -c 1048576 /dev/zero | curl -vvv -F 'test=@-' https://mensura.cdn-apple.com/api/v1/gm/slurp
  [...]
  {"DurationMs":11373,"Bytes":1048729,"BPS":92212}

(Excuse my really bad ADSL2+.)

The above is on Linux but I expect the effort to port that to macOS would be low. By all means post any needed modifications if you figure that out.