Corrects browser/store declarations: Firefox is desktop-only, Chrome now declares its supported API floor, and release-contract checks prevent unapproved manifest/permission drift. No runtime feature, permission, Sync schema, telemetry or backend change.

Fixes cross-device Settings conflicts so changing one preference can no longer overwrite a newer unrelated preference from another computer. Adds compact per-setting conflict clocks, keeps same-setting conflicts deterministic, and preserves existing Sync recovery/favicon behavior. No new permissions, telemetry, backend or remote code.

Hardened catastrophic Sync-loss recovery and added compact synchronization of manual detected-favicon choices. A previously healthy device now enters catastrophic-zero quarantine only when both getBytesInUse(null) reports zero and a full storage.sync.get(null) read is also empty. Persisted loss states receive a fresh browser-startup warm-up before recovery, and an MV3 worker interrupted during recovery observes a short persisted retry grace. Peers that observe an intentional reset remain safely waiting for a later authoritative profile instead of permanently dropping out of Sync, and the first complete post-reset profile replaces rather than merges the old pre-reset local state. Reset markers now require a non-empty initiating device ID. When the user chooses a detected favicon, MosaicSync synchronizes only a compact optional preference token; raw favicon URLs and image pixels remain local unless the existing Sync this image option is explicitly enabled. Receiving devices locally rediscover the preferred candidate through the existing bounded favicon pipeline. No new permissions, telemetry, backend, remote code, CSP relaxation or state/Sync schema-version change.

Added catastrophic Sync-loss containment and self-healing. An established MosaicSync device that previously observed a complete synchronized profile now treats a raw 0-byte storage.sync namespace as external loss: it preserves the local Personal/Work profile, enters a silent quarantine, and only after persistent confirmed absence republishes the valid local profile through the existing generation machinery and verifies the reconstructed remote copy. Recovery retains verified recent deletion tombstones and replays edits made during quarantine. MosaicSync-controlled Clear Sync copy now leaves a small versioned reset-intent record instead of intentionally creating a 0-byte namespace, so other 1.30.13 devices can distinguish an explicit reset from browser-side loss. Confirmed recovery status is localized in all supported UI languages. No new permissions, telemetry, backend, remote code, CSP relaxation, or change to existing shortcut/settings/profile schemas.

Update/reinstall safety hardening. MosaicSync no longer resets onboarding, Sync enablement/bootstrap status, applied revision markers or recovery metadata merely because Firefox/Chrome reports runtime.onInstalled with reason install. Genuine empty installs still receive the normal first-run defaults through the existing storage initializer, while any surviving layout/metadata is preserved across install-like recovery transitions. Added Firefox/Chrome lifecycle regressions for false-install, waiting-for-Sync, fresh-install, normal-update and downgrade/re-upgrade-shaped events. Also added a separate-ID Firefox development packaging path (mosaicsync-dev@xipinformatica.cat) so routine about:debugging testing cannot overlay the production AMO identity. The 1.30.11 live wallpaper/darkness preview fix remains intact. No new permissions, synchronized/profile schema, telemetry, backend, remote code or CSP relaxation.

Automatic rollback based on version [1.30.10].

Fixed a Settings appearance regression where changing the wallpaper or background darkness was saved immediately but did not become visible until Settings closed. MosaicSync now restores live wallpaper/darkness feedback through an isolated paint-contained preview layer while keeping the authoritative full-screen page wallpaper and root dim values frozen under the open Settings panel. Normal wallpaper changes, the main darkness slider, separate Light/Dark wallpaper selection and active Light/Dark darkness all preview immediately; closing Settings performs the existing single deferred authoritative commit. No new permissions, Sync/profile schema changes, telemetry, backend, remote code or CSP relaxation.

Zero-new-features background performance/refinement release. Complete device/profile snapshot generations that have already passed full decode and record/settings validation are now retained in a tiny worker-local cache bounded to MosaicSync's eight retained recent devices. Every reuse still revalidates the currently visible snapshot manifest, all expected chunks, chunk metadata, assembled length and compressed-data fingerprint before the cache may bypass repeated Base64 decoding, gzip decompression, JSON parsing and record-map reconstruction. Incomplete, corrupt, malformed or validation-failing generations are never cached as failures; previous-generation torn-delivery fallback remains intact and a later-completed current generation is accepted normally. Also made a historical Cross-Space equivalence test deterministic and removed a few proven-dead internal symbols. No new permissions, synchronized/profile schema, backend, telemetry, heartbeat, remote code, transport, UI or visual changes.

Zero-new-features efficiency/refinement release. Already-normalized New Tab preference mutations for Space names, multiple-Spaces state and synchronized Frequently Visited preferences now use an explicit trusted workspace-replacement path instead of repeatedly re-normalizing/image-hashing the same live state before the ordinary persistence boundary validates it. Personal/Work Sync publication also reuses the state already normalized by the local-mutation dispatcher, and the five-minute alarm avoids repeating the same pending-local journal retry inside its subsequent semantic freshness check. Added deterministic evidence regressions for local-vs-remote ordering, tombstone deletion dominance and same-key Settings races, and removed only proven-dead runtime symbols/CSS variables. All 1.30.8 Sync safeguards remain unchanged. No new permissions, synchronized/profile schema, backend, telemetry, heartbeat, remote code or user-facing changes.

Zero-new-features Sync concurrency hardening. MosaicSync now preserves short-lived bounded evidence for valid Personal/Work records/settings that Firefox/Chrome actually delivers through storage.onChanged, including a deterministically newer oldValue displaced by an expected own write. Before authoritative commit/reconciliation work continues, that evidence is compared with the current shared value through the existing deterministic conflict rule, closing the narrow same-key read→write race where a newer delivered value could otherwise be overwritten before the post-write ledger saw it. Added adversarial Personal/Work race tests plus foreground single-flight failure/freshness and frozen-input regressions. No new permissions, synchronized/profile schema, backend, telemetry, heartbeat, remote code, watchdog-frequency or user-facing changes.

Zero-new-features performance/refinement release. Trusted internal Cross-Space operations now reuse already-normalized state instead of repeating full image-heavy normalization; local writes and favicon commits reuse exact compact persisted baselines instead of rebuilding them. Simultaneous foreground Sync freshness requests from multiple New Tabs share one in-flight reconciliation while preserving immediate post-check freshness, and the foreground throttle now uses a monotonic clock. Publication avoids redundant serialization when the delivered remote record already wins, workspace clock changes use a positive fast path with semantic fallback for equal clocks, and unchanged Settings geometry avoids repeated root style writes. Proven-dead Settings CSS was removed without changing the single-scroll-owner architecture. No new features, permissions, synchronized/profile schema, backend, telemetry, remote code, heartbeat or watchdog-frequency change.

Zero-new-features Sync-resilience maintenance. An already-open MosaicSync New Tab now performs a throttled freshness reconciliation when it becomes visible/focused again or returns from bfcache, using the existing serialized Sync path and self-healing the existing five-minute watchdog alarm. A device-local diagnostics record captures Sync check/event timing and revision identifiers without telemetry or synchronized user data. Normal Personal/Work publications now preserve newer already-delivered remote records and build commit markers from the actual post-write ledger, preventing a missed Sync event plus a local edit from masking concurrent remote changes. No new permissions, synchronized/profile schema, server, heartbeat, CSP relaxation, telemetry, remote code or user-facing feature.

Zero-new-features Settings-stability refinement. 1.30.5 preserves the 1.30.4 single-scroll-owner Settings architecture and fixes a small follow-up found independently in two audits: changing MosaicSync's interface language while Settings is open now preserves the actual outer Settings scroll position instead of reading/writing the non-scrollable inner form. Added regression stress for repeated Separate Light/Dark Wallpapers and Frequently Visited visibility toggles. No permissions, schemas, CSP changes, telemetry, remote code or feature changes.

Stability-focused maintenance release. Settings now uses a single vertical scroll owner instead of an independently scrolling inner Settings form. This is a targeted fix for reproducible Firefox cases where expanding dynamic Settings sections such as Separate Light/Dark Wallpapers or Frequently Visited could leave the Settings shell visible while its contents became blank or unresponsive. No new features, permissions, storage schemas, CSP changes, telemetry, or remote code.

Zero-new-features stability release. Settings no longer uses Firefox's native modeless <dialog> after reproduced freezes while expanding Separate Light/Dark Wallpapers; the fixed panel keeps accessible dialog semantics and explicit close/Escape/outside-click behavior. Separate Wallpapers and Frequently Visited now minimize live layout/repaint work. Space switching is blocked while Settings owns a pending draft. Stale shortcut/wallpaper async jobs and System-theme reconciliation are generation-guarded. Favicon conventional-fallback timeouts remain provisional, durable favicon-recovery queue mutations are serialized/rebased and reject non-finite timestamps, and final slider interactions persist immediately. No new permissions, schemas, CSP changes, telemetry, remote code or features.

Zero-new-features Snow Leopard refinement release: Light/Dark theme switching now shows the matching configured wallpaper immediately while Settings remains open without invoking the broad launcher renderer; favicon quality completion no longer treats partial redirected/original-origin scans as complete; device-local favicon audit-ledger writes are serialized and reject non-finite metadata; cancelled manual favicon discovery cannot restart after awaited bookkeeping; identical render-manifest rewrites are avoided; and production Long Task diagnostics are developer-gated. No new permissions, schemas, CSP changes, telemetry, remote code or user-facing features.

Snow Leopard corrective maintenance release: fixes the remaining Settings blank-panel path by avoiding redundant own-write/global Settings reconstruction, completes bounded automatic favicon quality auditing so later better artwork can replace a quick low-resolution icon, filters permission-event work by feature, clarifies Sync source/receipt wording, removes obsolete Sync/CSS baggage, refreshes translations, and adds Galician. No new permissions, Sync/profile/storage schemas, CSP, telemetry, or remote code.

Snow Leopard maintenance release: fixes a Firefox/Linux Settings paint failure, improves automatic favicon quality recovery, clarifies Sync source/receipt wording, strengthens complete-profile Sync recovery tests, removes obsolete Sync/CSS baggage, corrects stale localization copy, and adds Galician. No new permissions or schema/CSP changes.

Snow Leopard maintenance release with no new features. Hardens Settings against cross-tab/storage races so pending edits cannot overwrite or be overwritten by newer external state; completes favicon quality discovery so large manifest icons cannot stop the search before a better conventional favicon is considered; consolidates the identical Firefox/Chrome New Tab runtime into one canonical build-time source; removes the unused monolithic New Tab stylesheet from runtime packages; and strengthens behavioral, localization, packaging and reduced-motion regression coverage. No new permissions or schema changes.

Improves complete Personal + Work Sync recovery, New Tab startup performance and Firefox rendering stability. Fixes the one-time white startup pill without breaking the MosaicSync hello mascot; prevents Light mode from briefly painting Dark tiles; keeps Settings stable while Separate Light/Dark Wallpapers or first-time Frequently Visited changes persist; fixes drag/drop localization; and improves general favicon quality ranking so oversized manifest/touch assets do not automatically displace a better conventional favicon. No new permissions.

Improves whole-profile Sync recovery and New Tab startup reliability/performance. Personal + Work now recover as one verified profile with previous-generation fallback, safe fresh-device waiting/merge behavior, and Work self-repair. New Tab keeps its fast critical launcher path while eliminating the Firefox one-time white-pill trigger: first logo hover no longer loads secondary CSS, and deferred CSS is isolated from already-painted launcher controls. Also improves wallpaper preview isolation, Frequently Visited preference Sync and shortcut hover. No new permissions.

Improves whole-profile Sync recovery and New Tab startup reliability/performance. Personal + Work now recover as one verified profile with previous-generation fallback, safe fresh-device waiting/merge behavior, and Work self-repair. New Tab uses a smaller critical path, visible-first artwork hydration and on-demand secondary UI CSS; Firefox no longer receives a deliberate post-first-paint stylesheet recascade. Also improves wallpaper preview isolation, Frequently Visited preference Sync and shortcut hover. No new permissions.

1.27.8.6 is a narrow Firefox first-frame native-control hardening follow-up to 1.27.8.5. The previous CSS-ownership cleanup was correct but did not eliminate the reported transient rounded "pill" on the user's Firefox hardware. Source review then found that the custom launcher Settings button remained a native <button> with the default appearance: auto, while a deferred stylesheet introduces generic button font/color rules after first paint.

This release explicitly suppresses native widget appearance in blocking critical CSS for the fully custom-styled Settings, Bookmarks and Space launcher buttons. The change is intentionally minimal so it can test/fix the native-control hypothesis without altering the delayed secondary-style architecture or any product/Sync behavior.

Hardened Firefox New Tab launcher controls against a transient native-button flash during startup. The custom Settings, Bookmarks and Space buttons now explicitly use appearance: none in first-frame critical CSS, with new cross-browser regression coverage. No permissions, Sync/profile changes, CSP relaxation, telemetry or feature changes.

Fixed a brief Firefox New Tab startup artifact caused by the deferred secondary stylesheet re-declaring launcher-visible Settings-button styles. Launcher tile and folder-mosaic artwork rules are now critical-only as well, and new regressions enforce the critical/secondary CSS ownership contract. No new permissions, Sync/profile changes, CSP relaxation, telemetry or feature changes.

Scope

1.27.8.4 is the third focused New Tab performance/stability pass for older/slower desktop CPUs. It refines the 1.27.8.3 critical-path work by removing duplicated critical CSS from the deferred UI stylesheet, shrinking the blocking launcher stylesheet further, starting authoritative local-state I/O before the large ES-module graph evaluates, and warming hidden folder artwork in bounded idle chunks instead of one delayed bulk read.

The release also fixes the Settings blanking regression triggered by separate Light/Dark wallpaper controls, synchronizes the Frequently Visited Show/Count preference while keeping actual browser-derived sites/history and permission device-local, and makes the paint-only shortcut hover enlargement more noticeable.

There are no new permissions or host permissions, no Sync shortcut/profile/container schema change, no conflict/tombstone change, no CSP relaxation, no telemetry/remote code, and no reduction of URL/image/SVG validation or artwork quality.

Mozilla Add-ons concise changelog

Performance/stability follow-up for older/slower computers. MosaicSync now uses a smaller launcher-only critical stylesheet plus a truly secondary-only UI stylesheet, starts authoritative local-state I/O before the main module graph evaluates, and hydrates hidden folder artwork in bounded idle chunks. Fixed the Settings blank/white regression when separate Light/Dark wallpaper controls change. Frequently Visited Show/Count now follows the synchronized MosaicSync profile while actual sites/history and the browser permission remain device-local. Shortcut hover enlargement is more noticeable without layout shift. No new permissions, CSP relaxation, telemetry or image-quality reduction.