{"status":"ok","head_age_days":1,"max_head_age_days":2,"chain_head":"8e667ba284e0df10b9a93f16b0de3871a92c23937b59166aa6cf34002aa5a70b","latest_block_date":"2026-10-26","block_height":89,"genesis_date":"2026-07-22","chain_format":"1","head_slice_sha256":"3fb87a11ec565fb7d38194484b8905001ce978a23034c69ec2314835583fcbbd","head_prev_block_sha256":"fcc040275cbdde6b0c11cb0e8eb22aa8c68342845f59d87abe25563914f08765","head_record_count":50531,"populations":{"mcp":317,"schema":50214},"spec_version":"1.0","spec_url":"https://github.com/nerqai/lastseen/blob/main/docs/HASHCHAIN-SPEC.md","notice":"Each daily block is SHA-256(prev_block + ':' + date + ':' + slice_sha256); the slice is the sorted canonical lines of every observation dated that day. Absence of a population on a day is NOT a zero row (interval-censored). The head is anchored in each Zenodo dataset version so it cannot be backdated."}