{
  "rollback_version": "V23",
  "experiment_id": "EXP-V21-...",
  "change_id": "CHG-...",
  "source_manifest_hash": "sha256:...",
  "generated_at": "2026-09-01T00:00:00Z",
  "strategy": "surgical_exact_reverse",
  "operations": [
    {
      "target_file": "page/index.html",
      "operation": "replace_exact",
      "before_exact": "ORIGINAL FRAGMENT",
      "after_exact": "EXPERIMENT FRAGMENT",
      "expected_occurrences": 1,
      "operation_signature": "sha256:..."
    }
  ],
  "guardrail": "Rollback reverses only after_exact -> before_exact and refuses if the controlled fragment no longer matches."
}