{ "id": "storage.0", "pos": [50, 121, 822], "xlen": 4, "zlen": 4, "rows": 9 }

1. Start a new creative world.
2. Open inventory > Options > Tools > Data dumps.
3. Go to the "Item panel" dump
4. Dump CSV and PNG (64x64).
5. Wait for dump to complete.
6. Copy /dumps/ to $web-root/items
7. Convert csv to JSON: ^([^,]+),(\d+),(\d+),(true|false),([^,]+)$ "$1/$3": "$5",
8. Remove duplicates?