JSON Patch

Since JSON is a subset of JS, I would have expected `.` to be the delimiter. That jives with how people think of JSON structures in code. (Python does require bracket syntax for traversing JSON, but even pandas uses dots when you generate a dataframe from JSON.)

When I see `/`, I think:

- "This spec must have been written by backend people," and

- "I wonder if there's some relative/absolute path ambiguity they're trying to solve by making all the paths URLs."

    {
      "a": {
        "b": {
          "c": []
        }
      }
    }