Missing 21 Consecutive BTCBVOLUSDT BVOLIndex Files — Official Archive Is Incomplete

The official Binance public-data archive is missing 21 consecutive daily BTCBVOLUSDT BVOLIndex files, covering the entire period from:

2025-12-15
through 2026-01-04

Expected path pattern:

data/option/daily/BVOLIndex/BTCBVOLUSDT/BTCBVOLUSDT-BVOLIndex-YYYY-MM-DD.zip

The files immediately before and after this interval are available, confirming that this is a specific hole in the archive rather than an incorrect path or unsupported dataset.

Missing dates:

2025-12-15
2025-12-16
2025-12-17
2025-12-18
2025-12-19
2025-12-20
2025-12-21
2025-12-22
2025-12-23
2025-12-24
2025-12-25
2025-12-26
2025-12-27
2025-12-28
2025-12-29
2025-12-30
2025-12-31
2026-01-01
2026-01-02
2026-01-03
2026-01-04

This is extremely frustrating and unacceptable for an official historical market-data archive. A continuous volatility index cannot simply lose three weeks of observations without any warning, explanation, status flag, or documented outage.

These missing files break reproducible research, contaminate time-series pipelines, force users to insert artificial values, and can silently corrupt machine-learning training datasets. Users should not have to discover a hole this large only after auditing thousands of timestamps manually.

Please:

Restore all 21 missing daily archives and their corresponding checksum files.
Confirm whether the underlying BVOL observations still exist.
Explain why this period disappeared from the public archive.
Document the incident if the data cannot be recovered.
Add automated continuity checks so this does not happen again.

Please do not close this as a client-side download problem. The requested archive objects themselves are absent from data.binance.vision.

Start by checking the listed data/option/daily/BVOLIndex/BTCBVOLUSDT/BTCBVOLUSDT-BVOLIndex-YYYY-MM-DD.zip paths on data.binance.vision and compare them with the available files immediately before and after the interval. Done means the 21 archives and checksum files are restored, the underlying observations are accounted for, the cause is documented, and continuity checks are added.

Written by the indexing model from the issue text.