# Roadmap This is the canonical order of work, not proof that a feature exists. **A step is not ready for implementation until its user-visible and architectural behavior is documented in the canonical docs.** Update [UX](UX.md), [architecture](ARCHITECTURE.md), and the relevant packaging/upstream documents before changing behavior. Record validation and limitations when the step closes. | Step | State | Goal | | --- | --- | --- | | STEP20A | DONE | Native compositor foundation | | STEP20B | EXPERIMENTAL | First scrollable runtime row | | STEP20C | NEXT | Viewport and multi-output correctness | | STEP20D | PLANNED | Multiple runtime rows | | STEP20E | PLANNED | Session V2 persistence | | STEP20F | PLANNED | QuickShell visualization | | STEP20G | PLANNED | Package and daily-use qualification | ## STEP20A — native foundation · DONE **Deliverables:** native layout enum/parser, workspace-local state, real tiled Row 0, insertion/removal/focus model, IPC exposure, isolated build/staging, headless tests. **Exit evidence:** [historical report](STEP20A.md) and current source/tests. **Documentation before implementation:** original architecture, upstream base, and package coexistence contract; current canonical versions are [Architecture](ARCHITECTURE.md), [Upstream](UPSTREAM.md), and [Packaging](PACKAGING.md). ## STEP20B — first scrollable row · EXPERIMENTAL **Deliverables:** logical horizontal geometry, bounded `scroll_x`, scene translation, focus visibility, workspace-local standard-layout toggle, headless visual evidence, patch export. **Exit evidence:** [historical report](STEP20B.md). The single-row proof is present, but it is not a general-use viewport guarantee. **Documentation before further implementation:** [UX](UX.md) and [Architecture](ARCHITECTURE.md) must keep the temporary sizing and scene boundaries explicit. ## STEP20C — viewport correctness · NEXT **Goal:** make the single-row viewport correct at workspace and output boundaries. **Planned deliverables:** clipping or an equivalent rendering strategy, matching hit testing, adjacent-output tests, resize/migration tests, and transaction-safe camera animation. **Exit criteria:** no cross-output visual/input leakage in the tested scenarios; camera and IPC remain consistent across transactions; standard layouts still pass. **Docs first:** review the [STEP20C viewport proposal](design/STEP20C_VIEWPORT_DESIGN.md), resolve the visual/input gaps found by the [PARTIALLY FEASIBLE isolated probe](design/STEP20C_FEASIBILITY_PROBE.md) and the [PARTIALLY FEASIBLE SceneFX subtree spike](design/STEP20C_SCENEFX_CLIPPING_SPIKE.md), then settle the resulting contract in Architecture and UX and update Known Limitations before implementation. The subtree spike proves a narrow tiled path but exposes a popup visual/input leak and unresolved damage, effect and package-maintenance gates. The [PARTIALLY_FEASIBLE popup ownership probe](design/STEP20C_POPUP_OWNERSHIP_PROBE.md) closes the sampled root/nested popup leak in an isolated build. The later [PARTIALLY_FEASIBLE valid-grab and hidden-owner probe](design/STEP20C_VALID_GRAB_HIDDEN_OWNER_PROBE.md) measures a real XDG grab and exposes a hidden-owner leak in that initial private clip; a further private guard closes the sampled leak. The later nested valid-grab probe closes only its sampled horizontal matrix; the separate vertical probe covers sampled Y-crossing popups. Further output geometries, transaction/output migration, complete damage/effects and packaging remain unresolved. None of these probes authorizes production STEP20C development or general multi-output support. The [source fixture for the valid-grab probe](../tooling/probes/step20c-valid-grab/README.md) preserves a bounded replay path. Its existence does not change STEP20C's **NEXT** status or any exit criterion. The [nested valid-grab probe](design/STEP20C_NESTED_VALID_GRAB_PROBE.md) is **FEASIBLE within its sampled horizontal headless matrix**: distinct valid grabs for parent and child popups, visual/input clipping, outside dismissal, hidden-owner camera return and standard-layout return were measured in a disposable guarded binary. Its [source fixture](../tooling/probes/step20c-nested-grab/README.md) is reproducible. The next bounded feasibility test should change output geometry with the same nested grabbed hierarchy and direct control comparison. Transaction, resize/migration, damage/effects and ABI/package gates remain open; this result does not change STEP20C's **NEXT** status. The [vertical-output nested-grab probe](design/STEP20C_VERTICAL_OUTPUT_NESTED_GRAB_PROBE.md) is **FEASIBLE within its sampled stacked-headless matrix**: both standard controls produced real Y-crossing A/B popup pixels and button targets, while the disposable guarded Mosaic build excluded sampled lower popup pixels/hits and preserved upper interaction, hidden-owner return and standard-layout return. Its [source fixture](../tooling/probes/step20c-vertical-grab/README.md) also reproduced the horizontal B-crossing control. The separate negative-origin comparison is recorded below. Scaling, rotation, resize/migration, transaction generations, complete damage/effects and dependency maintenance remain open. STEP20C stays **NEXT**. The [negative-origin nested-grab probe](design/STEP20C_NEGATIVE_ORIGIN_NESTED_GRAB_PROBE.md) is **FEASIBLE within its sampled signed-coordinate headless matrix**: HEADLESS-1 remained at `x=-800`, the virtual pointer reached both outputs, standard controls proved A/B crossing pixels and buttons, and the private guarded Mosaic build clipped sampled right-output pixels and hits. Hidden owner and `splith` return passed. Its [source fixture](../tooling/probes/step20c-negative-origin/README.md) preserves replay. Scaling, rotation, resize/migration, transaction generations, complete damage/effects and dependency maintenance remain open. STEP20C stays **NEXT**. The [temporal damage probe](design/STEP20C_TEMPORAL_DAMAGE_PROBE.md) is **PARTIALLY_FEASIBLE**: repeated XDG lifecycle and camera transitions restored sampled private Mosaic pixels and standard controls, and time-ordered private damage extents covered changed pixels between sampled captures. It did not identify every presented frame or bind camera/clip/input to a native applied transaction generation. Its [source fixture](../tooling/probes/step20c-temporal-damage/README.md) remains experimental. Its proposed headless presentation-event gate was examined by the subsequent probe below. Scaling, rotation, resize/migration, complete effects and dependency maintenance remain open. STEP20C stays **NEXT**. The [presentation identity probe](design/STEP20C_PRESENTATION_IDENTITY_PROBE.md) is **PARTIALLY_FEASIBLE**: native wlroots 0.20.2 headless present events were paired to commits by `(output, commit_seq)` and applied scene/clip snapshots were taken at the commit callback. Settled target states passed sampled clipping and input checks; faster commands could coalesce or defer. The actual buffer content of each commit and frame-specific pointer relation remain unproven. Its [private source fixture](../tooling/probes/step20c-presentation-identity/README.md) does not enter the production build. Its then-open buffer identity gate was examined by the subsequent private probe below. Scaling, rotation, migration/resize, complete effects/damage and SceneFX maintenance remain open. STEP20C stays **NEXT**. The [output buffer identity probe](design/STEP20C_OUTPUT_BUFFER_IDENTITY_PROBE.md) is **PARTIALLY_FEASIBLE** in this fixed matrix: 32 real GBM output-state buffers were read through FX texture APIs, correlated with native commits and headless presents. Twenty-eight were released on present and four early because HEADLESS-2 repaint reached a global release in the private instrumentation; the latter were not retained through present. Three second reads were byte-identical. Sampled popup pixels matched the applied scene/clip across three pairs with the same A/B popup objects; the initial logical/applied camera lag also had an identified buffer but no proven visual defect. Readback materially changed timing, and neither frame-specific pointer identity nor an atomic scene/input generation is proven. Its [private fixture](../tooling/probes/step20c-buffer-identity/README.md) is preserved experimental source, not a production dependency. The smallest next gate is a lower-impact buffer observation with an explicit applied scene/input generation, then separate effects/damage and SceneFX maintenance qualification. STEP20C stays **NEXT**. The [applied state/input probe](design/STEP20C_APPLIED_STATE_INPUT_PROBE.md) is **PARTIALLY_FEASIBLE** in its fixed headless matrix. A distinct private patch prevented the historical cross-output buffer release; three selected buffers were read and retained through native headless present, while a partial experimental epoch and real pointer traces exposed applied state at build and hit. Client delivery under grabs remained a separate observation. Incomplete mutation coverage, untested error paths and intrusive readback leave the temporal-consistency gate open. The next experiment was to map the mutation boundary with lower-impact observation before any production STEP20C decision. STEP20C stays **NEXT**; multi-output remains **NOT YET SUPPORTED**. The [mutation coverage probe](design/STEP20C_MUTATION_COVERAGE_PROBE.md) is **PARTIALLY_FEASIBLE** overall. A bounded trace-only matrix separated camera/clip, popup hierarchy, same-size client content and surface input region changes. The input-region test changed the actual scene hit while `asi_applied_epoch` was unchanged, so that counter is not a complete geometry/hit identity. Output destruction released one held reference in the real private compositor; rejected-commit cleanup is still untested on a backend. Whether SwayFX's existing event-loop ordering suffices for build/present/input coherence is **UNDECIDED**. The smallest next gate is a controlled hit-geometry mutation between one known output-state build and its deferred headless present, with hits and client delivery sampled on both sides. This remains scientific evidence, not production STEP20C. The independently replayed [commit/present/input ordering probe](design/STEP20C_COMMIT_PRESENT_INPUT_ORDERING_PROBE.md) tested that gate without changing backend scheduling. Twenty real input region mutations applied in two private modes, but none occurred between an accepted output commit and its matching headless present; P2 is **INCONCLUSIVE**. The sampled hit and client delivery matched effective input state, and no distinct Mosaic clipping defect was reproduced. The subsequent pending-input event-loop follow-up below addressed that bounded timing question without observing the target interval. STEP20C remains **NEXT** and multi-output **NOT YET SUPPORTED**. The bounded [event-loop pending-input probe](design/STEP20C_EVENT_LOOP_PENDING_INPUT_PROBE.md) decoupled normal client submission from IPC/client acknowledgements, then stopped after five attempts in each private mode. All 20 target mutations applied, with no matching commit-to-present interleaving. Close this particular temporal line as **INCONCLUSIVE / NOT EXERCISED** for the tested headless backend and fixed geometry. Do not infer an extra generation contract or production readiness. The next separate STEP20C gate should address complete effects/damage, scaling, or resize/migration. STEP20C stays **NEXT** and multi-output Mosaic **NOT YET SUPPORTED**. The [effects/damage probe](design/STEP20C_EFFECTS_DAMAGE_PROBE.md) then demonstrated genuine shadow spill in both standard controls, excluded the sampled spill under private Mosaic, and measured a visibly active translucent blur, sampled damage coverage and three exact settled camera returns. Its result is **PARTIALLY_FEASIBLE**: interior Mosaic shadow, optimized blur cache correctness, outside-viewport shader sampling, popup effects and saved buffers remain unqualified. The next distinct gate should test scaling first for the inherited clip and effect draw regions; rotation, resize/migration, saved buffers and ABI/package maintenance remain open. This does not authorize STEP20C production work or STEP20D. STEP20C stays **NEXT** and production multi-output Mosaic **NOT YET SUPPORTED**. ## STEP20D — multi-row Spatial Canvas · PLANNED **Goal:** connect rows to runtime tree, transactions, scene, input, and IPC. **Planned deliverables:** active-row navigation, row-local scroll/focus, deterministic insertion/reflow, in-row reorder, and between-row movement. **Exit criteria:** real tiled containers preserve identity and order across row changes; focus and camera restore correctly; headless multi-row tests pass. **Docs first:** settle exact interactions and row invariants in UX and Architecture. Unset key combinations remain TBD. ## STEP20E — Session V2 persistence · PLANNED **Goal:** restore Mosaic workspaces across sessions without creating a second runtime authority. **Planned deliverables:** durable activation, row order/membership, active row, scroll, focus, stable identities, and restart tests. **Exit criteria:** deterministic restore and safe fallback for missing windows/older snapshots. **Docs first:** specify persistence identity, versioning, failure handling, and ownership in Architecture and UX. ## STEP20F — QuickShell visualization · PLANNED **Goal:** expose compositor-owned Mosaic state in the desktop UI. **Planned deliverables:** workspace/row view and optional layout indication without duplicate QML layout state. **Exit criteria:** UI reflects IPC state and cannot contradict the compositor. **Docs first:** specify IPC consumer behavior and UI interactions in Architecture and UX. ## STEP20G — package and daily-use qualification · PLANNED **Goal:** publish a validated optional session while preserving standard SwayFX fallback. **Planned deliverables:** final Arch package, optional distinct session entry, install/rollback instructions, and a forward port proven against a newer SwayFX release. **Exit criteria:** package file ownership and coexistence verified, release build and headless/live qualification recorded, standard SwayFX updates remain independent. **Docs first:** update Packaging, Upstream, Development, UX, and Known Limitations with the intended release contract. Effects freeze audit: the historical campaign exceeded its three-pair budget (15 pairs in five Mosaic runs); all evidence is retained. A separate fresh rebuild reproduced the main counts with one pair under the corrected campaign guard. The traced reference had a different effective size, so instrumentation neutrality and its cause remain unqualified. See the [effects report](design/STEP20C_EFFECTS_DAMAGE_PROBE.md). This adds no contract. The preserved [fractional scaling probe](design/STEP20C_FRACTIONAL_SCALING_PROBE.md) is **PARTIALLY_FEASIBLE** for static 1.25 uniform/mixed and 1.5 mixed headless outputs. Actual modes/PNGs and logical pointer motion were calibrated. Sampled root/nested popup and shadow spill disappeared on the neighboring output; visible blur, terminal popup columns, two settled camera returns and available physical damage were consistent. Opaque tiled-overflow controls, permitted interior shadow, restored Mosaic hit, caches and intermediate frames remain unqualified. Ten failed early calibrations and their source-provenance limit are retained. The two-pair global budget was respected. The next distinct gate should test resize/migration of owner/output clips; rotation, saved buffers and ABI/package remain separate. This is evidence only: STEP20C stays **NEXT**, production multi-output **NOT YET SUPPORTED**, STEP20D–G **PLANNED**. The preserved [dynamic output ownership probe](design/STEP20C_DYNAMIC_OUTPUT_OWNERSHIP_PROBE.md) is **PARTIALLY_FEASIBLE**: actual logical resize 800→960→800 and workspace migration H1→H2→H1 retain workspace/tiled identities and update sampled applied tiled/root-popup clips. Vacated outputs show exact background after stabilization. Two standard controls fail final reference calibration through fixture occlusion; Mosaic's corrected calibration passes. Maximum-scroll clamp, migrated clipped popup input, independent opaque tiled spill, effects and intermediate frames remain unqualified. Budgets are exhausted at six reconfigurations and six migrations, with zero additional camera pairs. No production change follows. Rotation is the next separate geometric gate; other open STEP20C gates persist. The original temporary evidence manifest passed verification before an offline analyzer rerun replaced its bytes; see the report for provenance. STEP20C stays **NEXT**, multi-output **NOT YET SUPPORTED**. The [rotated-output probe](design/STEP20C_ROTATED_OUTPUT_PROBE.md) is **PARTIALLY_FEASIBLE** for sampled applied geometry, PNG/pointer calibration, hidden-owner return and physical damage. Its partial-popup clipping conclusion is **UNDECIDED** because the Mosaic popup never crossed the R90 boundary and the pristine R90 capture was lost to a fixture assertion. The next distinct geometric gate should force a legal grabbed Mosaic popup portion across that boundary with a completed pristine control. STEP20C remains **NEXT**. The [static R90 partial-popup gate](design/STEP20C_ROTATED_PARTIAL_POPUP_CLIP_PROBE.md) then measured exactly that B crossing and completed the pristine control. The bounded result is **PARTIALLY_FEASIBLE**: B's sampled pixels/input obeyed the owner clip, while the independent clipped-away A input point and broader temporal/effect cases remain open. Next prioritize saved transaction buffers against the same owner-derived viewport before optimized blur cache, interior shadow and ABI/package maintenance. STEP20C remains **NEXT**; production multi-output remains **NOT YET SUPPORTED**. The subsequent [saved transaction buffer campaign](design/STEP20C_SAVED_TRANSACTION_BUFFER_PROBE.md) observed real held XDG configure transactions, reused saved buffers, private render entries and sampled ACK/timeout removal. Its target never crossed the H1/H2 boundary after the applied Mosaic camera settled at 1760. Overall **INCONCLUSIVE**; all three run reservations are consumed. A new, separately authorized saved-buffer experiment must calibrate the applied camera and target crossing before the first transaction. Optimized blur/cache and SceneFX ABI/package remain separate unqualified gates. STEP20C stays **NEXT**, multi-output **NOT YET SUPPORTED**. The independent [saved target crossing campaign](design/STEP20C_SAVED_BUFFER_TARGET_CROSSING_PROBE.md) used one measured signed camera correction and observed the actual target saved node cross x=0, render inside H1 and retain permitted pixels. H2 showed no target color, but whole-image equality failed by a repeated 253-pixel reference difference. Mosaic timeout cleanup and held input remain untested after an E2 fixture pointer error. Result **PARTIALLY_FEASIBLE**, architecture **UNDECIDED**. The next narrow gate should first resolve the H2 reference artifact and complete a fresh target timeout/input observation; optimized blur/cache and SceneFX ABI/package remain later separate gates. STEP20C is still **NEXT** and multi-output **NOT YET SUPPORTED**. The saved-target freeze audit identifies the repeated 253-pixel H2 difference as strongly compatible with Kitty's blinking block cursor, not causally proven. A separate static-reference Mosaic timeout/input gate is authorized before optimized blur/cache and SceneFX ABI/package work. No production readiness or changed UX contract follows. The completed [static-reference saved-target natural timeout gate](design/STEP20C_SAVED_TARGET_TIMEOUT_INPUT_PROBE.md) then measured a real crossing target saved node, clipped H1 rendering, stable full-image H2 RGB, two targeted pointer hits and natural timeout cleanup with the XDG client alive and serial 50 withheld. Combined with the earlier E1 ACK, the tested saved-target clipping matrix is viable, while damage across every frame, broader input and GPU/texture lifetime remain unqualified. Its verdict is **PARTIALLY_FEASIBLE**; the earlier probe's own UNDECIDED conclusion is preserved. The next separate STEP20C gate is optimized blur/cache, followed by SceneFX ABI/package. STEP20C is still **NEXT**, production multi-output **NOT YET SUPPORTED**. The preserved [optimized blur cache probe](design/STEP20C_OPTIMIZED_BLUR_CACHE_PROBE.md) is **PARTIALLY_FEASIBLE**, architecture **UNDECIDED**. A real background layer under blur_tree triggered natural output-specific cache reconstruction and fresh central A/B/A filtered pixels in private splith and Mosaic. Sampled final tiled drawing excluded H2, whose whole RGB remained identical; output damage extents covered stabilized differences and sampled cache/FBO teardown completed. Shared boundary differences up to six RGB levels remain unresolved. Pristine C0 failed before captures through a duplicate configure fixture; its second initial image was reserved only after observation. No numerical budget was exceeded or run repeated. Instrumentation neutrality, whole-cache equivalence and intermediate frames remain unqualified. A separate pristine/untraced boundary-sampling gate should precede ABI/package qualification. This evidence freeze changes no production or UX contract. STEP20C stays **NEXT**, multi-output **NOT YET SUPPORTED**. The preserved [optimized edge causality gate](design/STEP20C_OPTIMIZED_BLUR_EDGE_CAUSALITY_PROBE.md) is **PARTIALLY_FEASIBLE**, architecture **UNDECIDED**. Four completed fixed negative-origin runs qualify pristine/private splith and same-binary Mosaic OPT-off/on controls. Pristine/private full images and Mosaic trace-off/on full images are exact at six homologous states; common glass across layouts is also exact. Historical right/bottom differences persist without new traces, with max RGB delta 6, fresh central pixels and stable whole H2. Native FBO history causality remains unproved despite source/model support. R3 damage extents cover stabilized differences only. No clipping regression or required invariant violation is established. A separate SceneFX ABI/package audit is now justified, retaining this shared rendering limitation; optional selective GPU observation requires a new scoped ticket. This evidence is preserved without a production change. STEP20C stays NEXT, production multi-output NOT YET SUPPORTED. The preserved [SceneFX ABI/package audit](design/STEP20C_SCENEFX_ABI_PACKAGE_FEASIBILITY.md) is **PARTIALLY_FEASIBLE**, architecture **SCENEFX_ABI_PACKAGE_REQUIRES_ARCHITECTURAL_DECISION**. The unchanged current package builds with stock SceneFX and stages exactly /usr/bin/swayfx-mosaic. The shared experimental binary needs two clip exports absent from stock despite the same SONAME. Static embedding builds and resolves without a SceneFX shared dependency, but shared wlroots interposition, updates, security maintenance and license notices remain gates. A distinct private shared library would require a new file-ownership decision; upstream API acceptance is unknown. No integration or packaging contract is approved. The historical audit is frozen as evidence; STEP20C stays NEXT, production multi-output NOT YET SUPPORTED. The preserved [static distribution contract dossier](design/STEP20C_SCENEFX_STATIC_DISTRIBUTION_CONTRACT.md) is **EXPERIMENTAL / PARTIALLY_FEASIBLE**, conclusion **STATIC_DISTRIBUTION_REQUIRES_CONTRACT_DECISION**. One private Meson DESTDIR stage of the hash-qualified static executable contains exactly `/usr/bin/swayfx-mosaic`; this proves file shape only. The 85 overlapping exports and 31/34 wlroots scene bindings into the executable remain explicit paired-version constraints, not automatically defects. Only the pinned SceneFX 0.5 / observed wlroots 0.20.2 pair has non-graphical evidence. Notices (including generated protocols), security ownership, upgrades, rollback and graphical semantics remain gates. A disposable notice-section extraction passes mechanically; legal distribution compliance is not approved. The upstream API dossier is preserved and not submitted. Production strategy: **NONE — USER DECISION REQUIRED**. Packaging/UX contracts are unchanged; STEP20C stays NEXT and production multi-output NOT YET SUPPORTED. ## Approved private STEP20C static candidate — 2026-10-13 The user approved four decisions for documentation and private prototypes only: private static SceneFX; separate complete notices under `/usr/share/licenses/swayfx-mosaic/`; project responsibility for embedded SceneFX maintenance; and qualification of each exact SceneFX/wlroots pair. See the [decision register and bounded runtime gate](design/STEP20C_STATIC_RUNTIME_AND_PACKAGE_CONTRACT.md). The current PKGBUILD, system SceneFX dependency, one-binary package, production sources and cumulative patch remain unchanged. The future private stage may contain only `/usr/bin/swayfx-mosaic` and justified regular notice files below the license directory. No private shared library, session, service, config or Sway symlink is allowed. No real installation is authorized. Mosaic owns monitoring, impact review, rebuild and requalification of embedded SceneFX fixes, including renderer/shaders/dependencies/ABI/buffer lifetime/clip/ damage changes. Before public distribution, a release maintainer and security reviewer must be designated; no names or SLA are assigned. Preserve exact source, patch, compiler/options/dependency, notice, test and artifact manifests. A new relevant dependency build requires header/symbol/shared-layout inspection, rebuild, relocation/model/staging/headless checks and graphical requalification of relevant paths, then a separate publication decision. No automatic update subsystem is added. Ordinary SwayFX upgrades remain independent and standard SwayFX remains the fallback. All other pairs are NOT QUALIFIED. These decisions do not settle popup UX or close STEP20C production gates. STEP20A DONE; STEP20B EXPERIMENTAL; STEP20C NEXT; STEP20D–G PLANNED. Production multi-output remains NOT YET SUPPORTED. The [private static runtime gate](design/STEP20C_STATIC_RUNTIME_AND_PACKAGE_CONTRACT.md) is **EXPERIMENTAL / PARTIALLY_FEASIBLE**, architecture **UNDECIDED**. Real `/usr` static build/model/stage/notices/loaded-library identity/headless startup pass. Sampled H1 target pixels survive with zero target colors on H2, but whole-H2 reference equality fails through a focus/decor mismatch; input and splith return are NOT TESTED after the single run stopped. No rerun or algorithm modification occurred. Distribution notice closure, named release/security roles and broader ABI/graphics gates remain open. STEP20C NEXT, multi-output NOT YET SUPPORTED. The [static focus/input/standard follow-up](design/STEP20C_STATIC_RUNTIME_FOCUS_INPUT_STANDARD_PROBE.md) is **EXPERIMENTAL / INCONCLUSIVE**, architecture **UNDECIDED**. One run reused the exact static binary, verified loaded wlroots/output geometry, calculated camera and observed the applied clip. A fixture incorrectly required stored current_border_width=0 under border none; actual IPC retained thickness 2 with empty decoration and full-size client rectangles. The run stopped before any PNG, click or splith transition. Those gates are NOT TESTED; no clipping defect or need for an algorithm change is demonstrated. No retry/build/production change occurred. A separately authorized corrected-fixture gate is required. STEP20C stays NEXT; production multi-output remains NOT YET SUPPORTED. The [static RGB/input/standard retest](design/STEP20C_STATIC_RGB_INPUT_STANDARD_RETEST.md) is **EXPERIMENTAL / FEASIBLE for the tested matrix**; its evidence is frozen for publication. The corrected shared IPC predicate/replay pass before the sole unchanged-static- binary run. Two full H2 references and all later H2 RGB are exact; H1 retains 182,214 target pixels, H2 zero, actual visible/reference/standard button pairs are delivered only to the right client. Targeted splith removes the native clip and retains ordinary pixels/input. The runner exits 1 only on terminal exit IPC after completed measurements and compositor exit 0; that raw failure is retained and separately diagnosed/revalidated offline. No algorithm, build, production, package or UX change follows. Wider static popup/effect/lifecycle, complete damage/generation, ABI/maintenance/notices gates remain open. D1–D4 persist; STEP20C stays NEXT and production multi-output remains NOT YET SUPPORTED.