partition spec.json

{
  "order": [
    "A",
    "F",
    "S",
    "N",
    "C"
  ],
  "partitions": {
    "F": [
      "F"
    ],
    "S": [
      "S"
    ],
    "N": [
      "N"
    ],
    "FS": [
      "F",
      "S"
    ],
    "FN": [
      "F",
      "N"
    ],
    "SN": [
      "S",
      "N"
    ],
    "FSN": [
      "F",
      "S",
      "N"
    ]
  },
  "head_and_anchor": "alwaysretained",
  "reversal": "eachoriginallegonce",
  "empty_selection": "notpartofthisnamedspineextension"
}