{
  "monthly_pages": [],
  "live_snapshots": [],
  "latest_snapshot": null,
  "random_selection": {
    "line": "Ten records from the field guide are chosen at random each day.",
    "blocks": [],
    "method": {
      "summary": "Ten records from the field guide are chosen at random each day. The pool is every content page in /sitemap.xml, minus pages drawn or linked by a snapshot's facts in the previous 5 days. The pool is sorted, shuffled with a Fisher-Yates shuffle driven by a keyed hash stream, and the first 10 go to the snapshot block, the next 10 to the /snapshots block and the next 10 to IndexNow.",
      "seed": "HMAC-SHA256(key = secret, message = \"XS1|\" + YYMMDD). The secret is published after the experiment, so every draw can be rerun.",
      "stream": "block i = HMAC-SHA256(key = seed, message = i as 4 bytes, big-endian); each block is read as eight unsigned 32-bit big-endian integers.",
      "shuffle": "For j from n-1 down to 1: draw r; limit = floor(2^32 / (j+1)) * (j+1); redraw while r >= limit; k = r mod (j+1); swap items j and k.",
      "arms": "Items 0 to 9 form arm S, 10 to 19 arm M, 20 to 29 arm I."
    }
  }
}