SP rectangle source to keys.json

{
  "inputs": [
    2760,
    11960
  ],
  "keys": [
    "70/69",
    "300/299"
  ],
  "outputs": [
    2800,
    12000
  ],
  "gains": [
    40,
    40
  ],
  "same_held_heads": [
    4206,
    13406
  ],
  "target_nodes": [
    1406,
    1406
  ],
  "gap_before": 9200,
  "gap_after": 9200,
  "gap_priestly_expansion": 10000,
  "status": "new source-mechanism provenance for an already established rectangle, not a new numerical alignment"
}