[masarray]

Documentation-only engineering handoff, no runtime or engine changes. Records verified multi-PR branch/SHA topology, the exact last CI-qualified consumer baseline, four operator-visible defects, root-cause hypotheses (KM-TEST loopback classification and six-vs-seven Explorer columns), correct safe implementation phases and acceptance criteria. It is deliberately draft and does not claim fixes are complete. New implementation work should branch off the verified cumulative #501 commit, keep guard/pin intact and validate against local IEDScout C264 simulator.

[masarray]

Reconciliation finding (2026-10-26): KEEP OPEN — unique archived field handoff. docs/C264_SAME_HOST_FIELD_HANDOFF_2026-10-10.md exists at original HEAD 4613838f608152a263b54adb84d07f85155a43cf (blob 9a9ef262cc046b9548bd73821b5ece46527478d6) but the file is absent at current RC 817c3910e8223fa2ac531a4426ada5d2d4bbbe50. The branch is not a clean ancestor of RC (diverged). Do not classify as integrated/obsolete by PR date; preserve the handoff, simulator evidence distinctions, and release limitations in its own branch. Next: compare to surviving C264 reports and #502, nominate a canonical sanitized archive destination if needed, and only then decide closure. This PR was docs-only and has no right to override later CodeVerified/PhysicalVerified source authority.

[masarray]

Reconciliation D3 — distinct C264 field handoff archived safely (2026-10-26)

Disposition: B — historical C264 same-host GUI/field handoff is preserved as a sanitized engineering archive, not as shipped-code equivalence. Close this documentary tracking PR unmerged with source branch intact.

Canonical replacement: C264 sanitized evidence archive, archive commit d7e512a234a020ac5a841e44fee039b431f11bb5, blob 260de207930dea76db9f77e052ae693012644a2d; dedicated maintenance/audit branch only.

Unique delta preserved: Original docs/C264_SAME_HOST_FIELD_HANDOFF_2026-10-10.md, blob 9a9ef262cc046b9548bd73821b5ece46527478d6, fully reviewed separately from #502 and retained on historical head 4613838f608152a263b54adb84d07f85155a43cf. Archive explicitly keeps its unique Explorer 7-header versus 6-header layout heuristic hypothesis, editable ComboBox PART_EditableTextBox centering at 100/125/150% DPI, aligned Fault Record header/row checkbox geometry and tri-state behavior, KM-TEST virtual adapter versus Npcap pseudo-loopback discrimination, route hint not GOOSE publisher proof, no-frame diagnostics, and Report Unknown/pending versus observed-but-rejected projections. Historic #504 P1 UI code checkpoint is identified as source evidence, not a proven current RC DPI outcome. No private endpoint values or unredacted evidence copied.

Safety: Original full document/branch remains reachable; historical simulator data is not taken as field FAT, physical GOOSE observed publisher, or release promotion. No code path, WPF GUI layout, MMS Write, engine lock, main, stable tag/asset, or CI workflow touched by this closure. There is no inference of semantic UI parity solely from document ancestry.

Follow-up: If the unique Explorer column mismatch exists on current RC, file a narrowly scoped test/GUI repair rather than reviving old source. Validate real adapter and report ingress with separate same-host evidence; preserve #606/#753, #615 and #729 safety gates. Reopen/reconcile if another exact unique 2026-10-10 requirement is shown missing.