Blame for openings.json

{
  "n_rows": 3810,
  "n_unique": 3810,
  "n_terminal": 2,
  "n_eco": 500,
  "volumes": {
    "A": 817,
    "B": 772,
    "C": 1250,
    "D": 614,
    "E": 357
  },
  "hf_card_n": 3704,
  "n_starts": 7852,
  "median_ply": 9,
  "max_ply": 36
}