Vault / Mirror Drift (historical)
Status: HISTORICAL (parallel-run surface retired at Switchover S125, 2026-05-20).
During the S120-S125 parallel-run window, every per-Q-G file in _Master_Canon/Q-G/ carried mirror_source + mirror_date frontmatter and this surface returned rows when a per-Q-G mirror diverged substantively from its legacy source-of-truth. Switchover retired the legacy source; _Master_Canon/Q-G/ is now sole canon and there is no second surface to drift against.
Existing per-Q-G files retain their mirror_source / mirror_date fields as historical provenance — those values describe the parallel-run mirror lineage, not a live drift relationship.
Parallel-run drift summary (S120-S125, closed)
Across the parallel-run window the audit policy was: legacy source wins on conflict during Phase 0 → Phase V; per-Q-G files win after Switchover. By S125 the drift relationship was structurally dissolved because the legacy source moved to 02_Working/Archive/OPEN_QUESTIONS_archived_pre_S125.md (no longer at its prior canonical path).
Replacement surfaces
Drift-class problems post-Switchover live on different audit views:
- Supersession Violations — entries with
status: approvedANDsuperseded_by != null - Schema Missing Fields — per-Q-G files missing required v0.3 §3 frontmatter fields
- Last-Verified Overdue —
last_verifiedmore than 60 days stale
Switchover gate criterion (closed)
The “Zero unresolved drift events in last 14 days” criterion (Sitemap v0.2 §12) was checked GREEN at S125 by Kevin’s call (no unresolved drift through Phase V). See Switchover Gate for the full audit trail.