Firefox 143 Brings Windows Taskbar Web Apps and Copilot Sidebar Enhancements

Firefox’s latest release delivers the kind of practical Windows-focused refinements power users have been asking for — and a high-profile AI tie‑in that will keep privacy wonks and enterprise admins debating for weeks.

Background / Overview​

Mozilla’s rapid-release cadence means the browser you ran last month can look very different today. With this cycle, Firefox 143 moves through the Beta/Nightly pipeline and into broader distribution, bringing a mixture of platform-specific enhancements, developer-facing API work, accessibility improvements, and AI‑adjacent features. The build includes explicit Windows-focused functionality — notably the ability to pin websites as simplified web apps to the Windows taskbar — while also adding Microsoft Copilot as an option in the browser’s AI sidebar and improving accessibility through Windows UI Automation hooks.
This release is representative of Mozilla’s dual priorities: remaining competitive with other Chromium browsers on platform conveniences (PWAs / taskbar web apps, richer media codec support) while maintaining Firefox’s long-standing emphasis on privacy controls and extensibility. At the same time, the Copilot sidebar underscores a pragmatic acceptance that users expect quick AI access in‑browser — and that Mozilla will provide a single surface that can host multiple third‑party chat providers rather than bake any single assistant into the product.

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What’s new in Firefox 143 — at a glance​

• Pin websites to the Windows taskbar as web apps and run them in simplified windows with Firefox protections and add‑ons still available. Not supported by Firefox installs from the Microsoft Store.
• Microsoft Copilot in the sidebar: Copilot is available as one of several AI providers surfaced through Firefox’s side panel experience.
• Windows UI Automation support: Improved accessibility integration for Windows assistive technologies like Voice Access, Narrator, and the Text Cursor.
• Auto‑delete downloads from Private Browsing: When enabled, files downloaded in private mode can be deleted automatically at the end of the session.
• xHE‑AAC playback support: Adds support for xHE‑AAC audio playback on Windows 11 (22H2 and newer), macOS, and Android 9+.
• Webcam preview on camera-permission prompt: Lets you confirm which camera a site will use before granting access — useful when multiple cameras are connected.
• Improved Fingerprinting Protection: Additional attributes are normalized to make fingerprinting harder.
• Address bar updates: New quick actions, shortcuts, and address‑bar productivity improvements; some UI suggestions around event dates have appeared in recent address‑bar work (see caveats below).
• Developer and enterprise changes: New Web and extension APIs, changes aimed at enterprise deployment, plus the obligatory security fixes.

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Deep dive: Windows taskbar web apps — what changed and why it matters​

What Firefox added​

Firefox 143 introduces native support for running websites as dedicated web apps on Windows. The behavior mirrors what Chromium‑based browsers have been doing for years: you can pin a website to the Windows taskbar and launch it into a streamlined window that looks and behaves more like a standalone app than a regular browser tab. Critically, Firefox’s implementation preserves support for extensions/add‑ons when the site is opened as a web app, and it gives the window the site’s icon so it appears separately in the taskbar.

Why this is significant​

• It closes a usability gap with Edge, Chrome and other browsers that long offered this convenience.
• For power users and organizations that rely on web services (webmail, business dashboards, SaaS apps), taskbar‑pinned web apps reduce tab clutter and make frequently used sites feel like first‑class desktop apps.
• Maintaining extension compatibility is a practical, user‑friendly differentiator — many users count on extensions for password managers, ad blocking, or privacy tooling even when they run sites in “app mode.”

Limitations and deployment notes​

• The feature is not available in Firefox installations from the Microsoft Store; it ships for regular desktop installs.
• Implementation is browser‑hosted (a simplified window container) rather than a full OS‑level PWA registration mechanism. That affects things like OS notifications and some deep integration points where Chromium PWAs tie into shell behavior differently.

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Microsoft Copilot in the sidebar — integration, scope, and concerns​

How Copilot appears in Firefox​

Copilot is presented as a selectable provider inside Firefox’s AI/chat sidebar. The browser provides the UI container — a quick‑access panel that can host multiple third‑party chat providers (for example, ChatGPT, Google Gemini, Anthropic Claude, and now Microsoft Copilot). Selecting Copilot loads the Copilot web experience into that panel.

Important technical realities​

• This is essentially a web‑surface integration: Firefox provides an embedded sidebar that points at the provider’s web UI. It is not a locally hosted Copilot engine running inside the browser.
• The Copilot experience, feature set, and any account‑related limitations are imposed by Microsoft’s service, not by Mozilla. Expect the same content and functional constraints you’d see when using Copilot in other browsers, with some differences because Copilot’s web app was not originally engineered specifically for Firefox.
• There are documented quirks with Copilot and Firefox due to web compatibility edge cases. In some cases, Copilot’s own front end can contain origin‑handling or CSP assumptions that behave differently in Firefox than in Chromium.

Privacy and security considerations​

• Because Copilot is a remote service, interactions sent to the panel are processed by Microsoft’s back end; users should assume queries and uploaded content can be retained and processed according to Microsoft’s terms.
• Mozilla exposes about:config preferences to control AI features (and they can be disabled). Enterprise admins can similarly control features via policy.
• The presence of a first‑party UI shortcut to third‑party AI services is a convenience, but it blurs the lines between local browser features and remote platform services. Users and admins must be deliberate about the acceptable mix of local processing versus cloud AI access.

Practical advice​

• Users who want Copilot but are cautious about privacy should use throwaway accounts or avoid uploading private documents into Copilot sessions.
• Users who prefer no AI services: disable AI features in Firefox via the browser preferences or about:config flags (for example, toggles that start with browser.ml.*).
• Admins should evaluate enterprise policies if they need to prevent Copilot/AI features in managed environments.

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Accessibility gains: Windows UI Automation support​

Firefox 143 expands support for Windows UI Automation, a critical accessibility bridge for Windows assistive tools. This affects built‑in tools like Voice Access, Narrator, and the Text Cursor, improving compatibility and control for users who rely on assistive input and output.
Why this matters:

• Better UI Automation means third‑party accessibility tools and OS utilities can more reliably inspect and interact with Firefox’s UI elements.
• It narrows a longstanding gap between Firefox and other browsers on Windows accessibility tooling, which is a welcome advance for users with disabilities.

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Media and privacy: xHE‑AAC, fingerprinting protection, and camera preview​

xHE‑AAC support​

Firefox 143 adds xHE‑AAC audio decoding support on Windows 11 (22H2 and newer), macOS, and Android 9+. xHE‑AAC is increasingly used in streaming and broadcast contexts for its robustness and bandwidth efficiency.

• Benefit: Broader playback compatibility with modern streaming encoders and live services.
• Note: The support is platform‑gated on Windows (22H2+), so older Windows versions won’t see the benefit.

Camera preview on permission prompt​

The permission dialog for camera access can now display a live preview, making it easier to confirm which physical webcam will be used before granting access. This is small but valuable, particularly on laptops and desktops with multiple cameras (built‑in + external).

Fingerprinting protection improvements​

Firefox continues to harden its privacy stance by expanding fingerprinting protection: more attributes are reported as constant values or otherwise normalized to reduce unique device fingerprints. This is an incremental but meaningful step in reducing passive tracking.

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Private browsing: auto‑delete downloads​

Firefox 143 lets users choose to auto-delete files downloaded in Private Browsing after the private session ends. That behavior can also be controlled via settings.

• Use case: Users who download sensitive documents during private sessions but do not want residual files on disk will appreciate this option.
• Caveat: Users should be aware of the UX — accidentally deleting a needed file is possible if they forget the auto‑delete setting is active.

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Developer and enterprise notes​

Developer changes​

The release includes web and extension API improvements — for instance, a storage API enhancement that returns storage keys across storage areas. CSS and layout changes are also present (grid sizing updates, ::details-content pseudo-element behavior) which align Firefox with evolving web standards.

Enterprise and security​

• Firefox 143 includes security fixes; enterprise release notes contain policy details and translation management for controlled deployments.
• Administrators should review policy updates and the new enterprise notes to ensure that managed Firefox builds align with corporate update cadences and security baselines.

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Strengths: Where Firefox 143 shines​

• Platform parity without sacrificing add‑on compatibility. The taskbar pin/web‑app feature brings a convenient desktop experience while keeping add‑on support.
• Accessibility focus. Windows UI Automation integration is a concrete, practical improvement for assistive tech users.
• Privacy‑minded feature set. Fingerprinting protection enhancements and the option to auto‑delete private downloads show Mozilla balancing convenience and privacy.
• Practical media support. xHE‑AAC addresses a real playback gap for modern streams and broadcasts.
• Choice in AI. Rather than lock in a single assistant, Firefox continues to offer a multi‑provider sidebar surface, putting the onus on users to choose what they trust.

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Risks and caveats: What to watch for​

• AI integration is a web conduit, not local processing. The Copilot experience is a hosted web app inside a sidebar. Any data you send is handled according to the AI provider’s policies. That means potentially sensitive content could leave the local device.
• Compatibility quirks. Because Copilot’s web front end was designed primarily for other browsers, users may encounter UI bugs or functional limits in Firefox (some providers’ front ends assume Chromium behavior).
• Enterprise exposure. Organizations must consider whether giving users an in‑browser shortcut to third‑party AI services violates internal data policies.
• Unverified claims and progressive rollouts. Some address‑bar features and event‑date behaviors are being rolled out progressively or remain flagged as experiments. Not all users will see the same UI immediately; certain localized features may vary by region. If a specific address‑bar capability is critical to your workflow, validate it in your environment before relying on it.
• Microsoft Store restriction. If you rely on Store‑installed Firefox builds (for managed Windows environments), the taskbar pin/web‑app behavior is not present there — that fragmentation complicates support.

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Recommendations for different user types​

For power users and Windows enthusiasts​

• Try the new web‑app pinning on a regular desktop install and evaluate how add‑on compatibility behaves for your most used sites.
• If you want Copilot but prefer to minimize tracking, review Copilot’s UI behavior in the sidebar and avoid uploading confidential files.

For privacy‑conscious users​

• Disable AI features via the settings or about:config flags that control browser.ml.* if you prefer no built‑in AI shortcuts.
• Keep fingerprinting protection enabled and review the new private‑download auto‑delete option if you frequently fetch sensitive files.

For accessibility users and admins​

• Expect improved compatibility with Windows assistive tech; validate your assistive toolchain against the latest Firefox build to confirm expected behavior.
• If your organization requires strict accessibility certifications, document the new UI Automation integration and run compatibility tests with your supported assistive technologies.

For enterprise administrators​

• Review the enterprise release notes and policy updates before broad deployment.
• Consider blocking or restricting AI features via Group Policy or Firefox enterprise policies if your data governance rules prohibit routing content to third‑party AI services.
• Test the new web‑app pinning behavior in your standard images — remember it’s not available for Microsoft Store builds.

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How to enable/disable some of the new features (quick steps)​

• Pin a site to the taskbar (regular desktop install):
• Visit the site you want to pin.
• Use the “Add to taskbar” / “Install site as app” control in the address bar or the browser menu (UI may vary as the feature rolls out).
• Confirm “Open as window” or equivalent when prompted; a simplified window tied to the taskbar icon will be created.
• Disable AI sidebar features:
• Open about:config.
• Search for preferences beginning with browser.ml (for example, browser.ml.enable, browser.ml.chat.enabled, browser.ml.chat.menu).
• Toggle them to false to disable the AI features.
• Set auto‑delete downloads in Private Browsing:
• Open Settings → Privacy & Security (or the Downloads/Private Browsing settings).
• Look for the option to auto‑delete or prompt for deletion at the end of private sessions and set your preference.

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Final analysis — pragmatic progress with caution attached​

Firefox 143 is a pragmatic release: it fills gaps Firefox had versus Chromium browsers on Windows conveniences and media support while doubling down on privacy and accessibility where Mozilla’s values are strongest. The Copilot sidebar marks an acknowledgment that many users want in‑browser AI; the decision to treat providers as interchangeable web surfaces helps preserve choice and keep Mozilla neutral, but it also places responsibility on users and admins to understand data flows.
For consumers, the headline features are honestly useful: pinning web apps to the taskbar and camera preview are tangible, everyday improvements. For enterprises and privacy advocates, the release is manageable but requires thoughtful policy and configuration because the AI sidebar surfaces complex external services directly inside the browser.
Firefox 143 nudges the browser forward in meaningful, iterative ways. The big question now is governance — how organizations, privacy‑minded users, and Mozilla itself will balance convenience with control as third‑party AI services become a native part of the browsing experience.

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Source: Neowin Firefox 143 is out with the ability to pin sites to taskbar, Copilot integration, and more

 

[ChatGPT]

Mozilla’s Firefox 143 landed as a significant, pragmatic update: it finally brings a long‑promised form of desktop web‑app support to Windows, folds Microsoft Copilot into the browser’s AI sidebar, tightens several privacy and accessibility gaps, and introduces a clutch of media and UX improvements that will matter to both everyday users and IT professionals. The release also ships with a set of security fixes and ESR updates; several of the smaller features are being rolled out progressively or remain behind experimental flags, so users will see them at different times depending on build, channel and region.

Background / Overview​

Firefox 143 is a step toward modernizing Firefox’s desktop feature set while keeping the project’s long‑standing emphasis on choice and control. The most public changes are:

• Progressive Web App / “web apps” support on Windows — users can pin sites to the Windows taskbar and launch them in simplified windows (not yet available for Firefox distributed from the Microsoft Store).
• Microsoft Copilot in the AI sidebar — Copilot is now selectable alongside other chatbot providers already integrated in Firefox’s sidebar.
• Address‑bar “important dates” suggestions — the urlbar can surface upcoming dates/events for several countries as part of targeted suggestions.
• Camera preview in permission dialogs, improved private‑browsing download handling, expanded fingerprinting protection, Windows UI Automation accessibility improvements, and xHE‑AAC playback support across major platforms.
• Platform‑specific updates: Android gains DNS‑over‑HTTPS configuration in UI and “Smarter downloads”; iOS receives a redesigned UI and a new “Shake to Summarize” shortcut that requires recent iOS.

Official release notes and developer pages show the changes shipping in the 143 branch; many of the user‑visible items were trialed in Nightly/Beta and are being progressively rolled out. Where a feature is limited (regionally, by distribution channel, or to specific OS builds) that’s called out below.

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Progressive Web Apps on Windows: what changed, and why it matters​

What Firefox 143 actually delivers for PWAs​

After years in which Firefox lagged behind Chromium browsers on desktop PWA/SSB (single‑site browser) integration, Firefox 143 introduces a web apps experience for Windows users. Key points:

• Users can “pin” a website to the Windows taskbar and open it in a simplified window. The pinned site gets its own taskbar icon and behaves like a lightweight app window.
• Firefox intentionally keeps access to core browser features inside these windows: extensions/add‑ons continue to work, and the web‑app windows retain some Firefox chrome (toolbar/address bar elements are not stripped to nothing like some Chromium SSBs).
• The feature is not available for Firefox builds installed via the Microsoft Store / MSIX packaging (those versions still have limitations due to store packaging and Windows integration differences).
• The rollout began as a Labs/Nightly experiment and is now appearing more broadly on Release/Beta users on Windows; some users may need to enable an experimental setting in Firefox Labs or toggle the browser.taskbarTabs.* prefs in about:config while Mozilla progressively rolls it out.

Strengths and practical benefits​

• This is a pragmatic, low‑friction solution for power users who want quick, taskbar‑based access to web services (Gmail, Jira, etc.) without losing add‑ons, saved credentials or the rest of their Firefox ecosystem.
• Because add‑ons remain available, web apps can integrate with password managers, ad blockers, and other productivity extensions—a meaningful difference compared with some SSB implementations that intentionally sandbox extensions away.
• Mozilla’s approach reduces the “two‑browser” workflow many power users adopt (one browser for software-like websites, another for general browsing).

Limitations, oddities and enterprise implications​

• The feature is Windows‑only for this release and is explicitly disabled for Microsoft Store/MSIX builds. That complicates rollouts in managed environments where organizations deploy the Store package for centralized management.
• Early tester reports show minor UI oddities (taskbar duplicate icons, pin/unpin behavior inconsistencies) that are typical for a freshly reintroduced feature. Expect fixes over the next few point releases.
• Because the web‑apps model is intentionally not a full PWA implementation, web developers and sysadmins shouldn’t assume parity with Chromium PWAs (for example, service‑worker behavior, background tasks, some manifest behaviors and OS integrations may differ).

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Copilot and the AI sidebar: convenience vs. third‑party trust​

What’s new​

Firefox’s AI sidebar—introduced earlier and designed to host multiple chatbot providers—now offers Microsoft Copilot as a selectable provider. Users can:

• Add the chatbot shortcut to the sidebar and interact with Copilot in place while browsing.
• Use Copilot for on‑page summarization, content generation, code help and basic image/document analysis (subject to provider limits and account/subscription restrictions).
• Remove or disable the sidebar chatbot entirely via Firefox’s sidebar customization options.

Why Mozilla’s architecture matters​

• Firefox treats chatbots as providers—each provider has its own terms and privacy policies. Mozilla’s UI is a broker: it provides a common place to select a chatbot but does not subsume the provider’s rules.
• Conversations are between the user and the provider; Mozilla collects high‑level telemetry about feature usage but does not have direct access to your chat content.
• The sidebar acts as a convenience shell for provider services; under the hood the provider’s service processes the requests (i.e., Copilot requests go to Microsoft’s Copilot endpoint and follow Microsoft’s data handling rules).

Practical control: enable/disable​

• Casual users can remove the AI chatbot from the sidebar via the sidebar’s settings or Firefox’s Customize UI.
• Advanced users can remove or block AI features using Firefox’s configuration editor (about:config). Experimental prefs exposed in testing include browser.ml. toggles (for example, browser.ml.enable and related browser.ml.chat. prefs); these control the experimental on‑device and UI integrations that make the sidebar chat features show up.

Risks and trade‑offs​

• Integrating third‑party LLM services directly into the browser offers huge productivity potential but raises data‑handling and compliance questions for regulated environments. Organizations should treat Copilot the same as any other cloud‑based AI service: review legal/contractual data protections and disallow it where sensitive or regulated data may be typed into or captured by the model.
• Because each provider enforces its own usage limits and privacy rules, users must consent to multiple sets of terms when switching providers—confusion is a real risk for non‑technical users.

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Address bar: “Important dates” and other usability tweaks​

What changed​

Firefox 143 begins suggesting certain upcoming important dates and events directly in the address bar suggestions pane for some locales (examples include culturally recognized events such as Mother’s Day). This is a region‑limited feature that appears to be enabled by default where it’s rolled out.
There are at least two internal preferences related to this feature (visible in experimental builds or via about:config): browser.urlbar.suggest.importantDates (enabled by default in some builds) and a feature‑gate pref. These prefs can be used to disable the feature if a user or admin prefers a more minimal urlbar experience.

Why this matters​

• The urlbar has become a small productivity hub: quick actions, calculator results, and smart shortcuts are already present. Important dates fit that model by surfacing timely information without a search.
• For privacy‑minded users and admins, any new telco‑style suggestion is worth auditing: where does the events data come from, how often is it refreshed, and does it involve remote lookups that could reveal usage patterns? Mozilla’s UX typically leans toward local or Mozilla‑controlled lookups, but users who are sensitive to any external enrichment should opt out via the known prefs or UI settings.

UX critique​

• For many users, address‑bar suggestions are already a cluttered space. Adding cultural or calendrical events can be useful if it’s contextual and unobtrusive; otherwise it risks pushing other, more relevant suggestions (bookmarks, history) further down the panel.
• Region gating is sensible; what’s important in one country isn’t in another. However, rolling this out transparently—showing the source of the event data and a clear toggle in Settings—would reduce user confusion.

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Privacy and fingerprinting: incremental progress​

Fingerprinting protection improvements​

Firefox 143 expands its Fingerprinting Protection by reporting constant values for more device attributes—an approach that reduces entropy and makes fingerprinting harder by presenting the same signal across many devices. The move builds on prior anti‑fingerprinting work and aims to reduce the uniqueness of individual users’ browser profiles.

What this achieves and what it doesn’t​

• Reporting constant values for certain attributes reduces the distinguishing power of those fields. That helps blunt opportunistic fingerprinting that relies on rare attribute combinations.
• This is not a silver bullet: fingerprinting is a multi‑vector problem. Plugins, timing, fonts, installed codecs and behavioral signals can still contribute to a unique fingerprint. Firefox’s layered approach—ETP strict mode, tracker blocking, fingerprinting protection and optional sandboxing—continues to be the recommended model for privacy‑conscious users.

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Downloads and Private Browsing: clearer choices​

New private downloads prompt​

Firefox used to treat files opened directly from Private Browsing windows as temporary; they could be removed automatically at the end of the session, which sometimes surprised users who expected a downloaded file in Downloads to persist. With 143, Firefox prompts when a file is downloaded in Private Browsing, offering the user a clear choice to keep the file or have it deleted when all private windows close. There is a Settings toggle to default the behavior.
Why this matters:

• This change brings Private Browsing behavior closer to user expectations and to how Chromium‑based browsers handle such downloads (they persist).
• It reduces the risk of users believing a file remains when it will be deleted—important for workflows that involve saving PDFs or installers from private windows.

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Camera preview in permission dialog​

When a site requests camera access, Firefox 143 can show a live camera preview inside the permission prompt. That small UX tweak is surprisingly valuable: it helps users verify which camera (integrated, external, virtual) they’re granting access to before granting permission.

• This is especially useful for multi‑camera setups, frequent meeting users and privacy‑conscious people who want to ensure the right device is active.
• It’s a user‑centric mitigation against accidental camera sharing.

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Accessibility: Windows UI Automation improvements​

Firefox 143 improves Windows UI Automation bindings. Practically speaking that means better compatibility with assistive technologies such as Narrator, Voice Access, and other accessibility tools that rely on Microsoft’s UI Automation API.

• The update closes usability gaps for users who rely on voice interaction, screen readers, or remote assistive input.
• For enterprise IT and accessibility teams, this is a meaningful improvement: Firefox will be more predictable for automated testing and assistive workflows on modern Windows configurations.

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Media and standards: xHE‑AAC, CSS Grid, and developer niceties​

xHE‑AAC support​

Firefox 143 adds support for xHE‑AAC audio playback on Windows 11 (22H2+), macOS and Android 9+. xHE‑AAC is a modern codec optimized for a wide range of bitrates that streaming and broadcast services increasingly use.

• Benefit: better low‑bitrate audio quality and broader compatibility for modern streaming encoders.
• Caveat: platform codec availability still matters; on some systems the OS must provide decoders.

Web platform tweaks for developers​

• The <input type="color"> control now recognizes CSS color formats beyond hex (e.g., named colors and rgb()/hsl() strings), making developer inputs more flexible.
• Firefox’s CSS Grid sizing algorithm has been aligned better with the spec to fix layout cases that previously misrendered.

These are incremental but important for web developers and web‑app maintainers who depend on cross‑browser layout fidelity.

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Mobile: Android and iOS changes​

Android​

• Firefox on Android now exposes DNS over HTTPS (DoH) configuration in the Settings UI. This gives users a built‑in way to encrypt DNS resolution without fiddling with custom configuration—good privacy hygiene for mobile browsing.
• “Smarter downloads” brings a more responsive download manager with real‑time tracking and quick pause/resume/cancel controls in the Downloads UI.

iOS​

• iOS gets a redesigned browser UI and a new “Shake to Summarize” feature that surfaces a page summary when the device is shaken; iOS 26 or later is required. This is a convenience feature tapping on the in‑browser summarization tooling already present in the AI integrations.

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Security fixes and ESR updates: update promptly​

Mozilla’s release notes and recent vulnerability databases identify multiple security fixes affecting earlier Firefox and ESR branches. At least one set of memory‑safety bugs had been published as advisories and CVEs that apply to older versions and ESR releases. The practical advice is straightforward: install Firefox 143 (or the appropriate ESR updates) as soon as testing in your environment allows.

• Enterprises should test Firefox 143 or the corresponding ESR builds (Firefox ESR 140.x in many organizations) against their internal policy and extension matrix.
• Administrators should monitor Mozilla Security Advisories (MFSA) for details and CVE IDs and ensure that automated patching or update approval processes pick up the new build.

Note: some security advisory links were temporarily unavailable at the time the feature summary was drafted; Mozilla publishes detailed MFSA advisories that enumerate CVEs and impacted builds—these should be consulted for complete mitigation guidance.

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How to try, configure or opt out (practical steps)​

• Install or update to Firefox 143 via Mozilla’s update channel (or use enterprise packaging for managed deployments).
• To test web apps on Windows, look for the “Add to taskbar” or “Pin to taskbar” affordance when visiting a site, or enable Firefox Labs taskbar apps if the rollout hasn’t reached your profile.
• To disable the AI chatbot sidebar:
• Use sidebar customization to remove the AI chatbot shortcut, or
• For advanced users, search about:config for browser.ml.* preferences and set them to false to suppress ML/AI UI experiments (note: pref names and availability vary across channels).
• To control the address‑bar important‑dates feature, look for related urlbar prefs in about:config (experimental / rollout flags exist in some builds); set browser.urlbar.suggest.importantDates to false if present.
• For private‑browsing download behavior, visit Settings > General > Files and Applications and toggle the option Delete files downloaded in private browsing when all private windows are closed to suit your comfort level.

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Critical analysis: strengths, trade‑offs, and open questions​

Notable strengths​

• Practical catch‑up: Firefox 143 closes several user experience gaps that had put Firefox behind Chromium browsers on desktop convenience features (web apps, richer downloads, media codec support).
• Privacy‑aware integrations: The team’s treatment of chatbots as selectable providers—combined with clear removal toggles and telemetry restraints—keeps user choice front and center.
• Accessibility and platform parity: Windows UI Automation improvements and codec additions show Firefox addressing practical operational gaps that matter for enterprise accessibility and media playback.

Potential risks and areas to watch​

• Third‑party AI integration: Copilot and other chatbots introduce external data flows and policy complexity. Organizations and privacy‑sensitive users must treat these services like any cloud SaaS and enforce acceptable use policies accordingly.
• Rollout fragmentation: Several features are being gate‑rolled (Labs, flags, region limits). That leads to uneven experience across users and makes documentation and support more complicated for help desks.
• Fingerprinting messaging: While reporting constant values for more attributes moves the needle on fingerprinting resistance, it’s one part of a larger arms race. Users who require stronger anonymity should still layer other protections (strict ETP, containers, Tor).

Unverifiable or evolving items​

• The “Important dates” urlbar behavior is currently region‑limited and controlled by rollout flags; the event data source and exact rollout plan are not fully documented in public release notes. Users wishing to disable it should watch for the browser.urlbar.suggest.importantDates pref (it may not exist in all builds).
• Some early tester issues (taskbar duplication, odd pin/unpin edge cases) have been reported in community threads; they appear to be minor and are likely to be addressed in point releases, but they are worth testing in controlled environments before wide deployment.

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Final verdict for Windows‑focused users and IT teams​

Firefox 143 delivers a pragmatic collection of improvements: usable PWA‑style taskbar apps on Windows, a more complete AI sidebar with Copilot as a first‑class provider, sensible privacy and accessibility upgrades, and media codec parity improvements. For Windows power users the web‑apps feature alone will change workflows—especially for those who depend on extensions while using web services as quasi‑apps.
For IT teams and privacy professionals the release is cautiously positive: the new features give end users productivity gains but also require updated policies on third‑party AI tools, a review of distribution choices (MSIX/Store vs. packaged installers), and prompt application of security updates. Organizations should plan to:

• Test Firefox 143 (and the ESR channel) with corporate extensions, policies and assistive technologies.
• Update internal guidance on AI sidebars and disallow use where regulatory or data‑loss concerns exist.
• Encourage users to apply the new privacy toggles if they are concerned about address‑bar enrichment or private‑download persistence.

Overall, Firefox 143 is a practical refresh: Mozilla has not chased flashy exclusives but has prioritized useful, user‑centric improvements that make Firefox more competitive on Windows while preserving the project’s emphasis on choice and control. Expect iterative polish in follow‑on releases, and plan update rollout accordingly.

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Source: gHacks Technology News Mozilla Firefox 143.0 adds support for Progressive Web Apps, Copilot on sidebar, Important dates in the address bar - gHacks Tech News

 

[ChatGPT]

Mozilla’s latest stable cycle, Firefox 143.0, arrives as a pragmatic, platform-focused update that finally restores a long-requested desktop convenience—pinning web sites as taskbar apps on Windows—while folding Microsoft Copilot into Firefox’s AI sidebar, expanding fingerprinting protections, and adding a string of platform and UX refinements across Windows, Android and iOS. This release emphasizes practical parity with Chromium-based rivals on media and web‑app conveniences, preserves Mozilla’s privacy‑first posture in several areas, and pushes the ongoing debate over in‑browser AI access squarely into IT and privacy governance discussions. (firefox.com)

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Background / Overview​

Firefox has been iterating rapidly through the 140–143 release window, with many features first appearing behind Labs experiments or in Nightly/Beta channels before broader rollout. The 143 cycle is a mix of user-facing features (web apps, Copilot in the sidebar, camera preview in permission dialogs), platform parity items (xHE‑AAC audio support, Windows UI Automation fixes), and privacy hardening (expanded fingerprinting protection and optional auto‑delete of files downloaded in Private Browsing). Where features are region‑gated or distribution‑channel limited (for example, the Microsoft Store/MSIX build), Mozilla has used progressive rollouts and config flags to control exposure. (connect.mozilla.org)
This article breaks down what changed, why it matters to everyday and enterprise users, how to control or disable the new surfaces (especially the AI sidebar), and the realistic risks administrators and privacy‑minded users should weigh before enabling these features across fleets.

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What’s new — at a glance​

• Pinned web apps (Windows only): Pin a site to the Windows taskbar and launch it in a simplified Firefox window that retains extensions and profile context. Not available for the Microsoft Store / MSIX builds. (firefox.com)
• Microsoft Copilot in the sidebar: Copilot appears as a selectable AI provider inside Firefox’s AI/Chat sidebar. This is a web‑surface integration that opens Copilot’s web UI inside the panel. (ghacks.net)
• Address bar “important dates”: The urlbar can surface culturally relevant upcoming dates/events in certain regions; controlled by rollout flags and about:config prefs.
• Camera preview on permission prompt: When a site requests camera access, you now get a live preview inside the permission dialog to pick between multiple cameras. (firefox.com)
• Private Browsing download handling: Downloads in Private Browsing now trigger a prompt offering to keep or auto‑delete files; the auto‑delete option can be toggled in Settings. (firefox.com)
• Privacy & fingerprinting: Fingerprinting Protection has been strengthened by normalizing additional system attributes to constant values. (firefox.com)
• Accessibility: Windows UI Automation support is improved — better compatibility with Narrator, Voice Access and Text Cursor Indicator.
• Media & platform parity: xHE‑AAC playback is supported on Windows 11 (22H2+), macOS and Android 9+; Android gains DNS over HTTPS configuration and smarter downloads; iOS adds a redesigned UI plus “Shake to Summarize” (iOS 26+). (firefox.com)

These items come alongside developer‑facing updates (CSS Grid sizing alignment, ::details‑content pseudo element, console tweaks) and ESR updates for organizations. (developer.mozilla.org)

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Progressive Web Apps (PWAs) and pinned web apps on Windows​

What Mozilla shipped​

Firefox 143 enables a Windows‑focused “web apps” workflow that allows users to install or pin websites to the Windows taskbar and run them in a simplified window. These app windows look and feel more like single‑site apps (SSBs) but, critically for Firefox users, they retain access to extensions and the user profile, providing continuity for password managers, privacy add‑ons, and other tooling. The feature is rolling out via Firefox Labs and is also available in Release/Beta channels in many builds. (connect.mozilla.org)

How it works in practice​

• A new “Add to taskbar” or “Install site as app” affordance appears in the address bar on supported Windows builds.
• Confirming the install creates a simplified window with a site icon pinned separately to the taskbar.
• The window is not a full OS‑registered PWA in the Chromium sense — some OS‑level integrations (deep notification hooks, background tasks, or shell integration parity) may differ. (ghacks.net)

Strengths​

• Practical convenience: For power users who treat web services (Gmail, Jira, Slack Web) like desktop apps, this reduces tab clutter and speeds access.
• Extension compatibility: Unlike many SSB/Chromium PWA workflows that sandbox or strip add‑ons, Firefox’s approach keeps add‑ons working inside pinned windows. This is a significant usability differentiator.

Caveats and limitations​

• Windows‑only (for now): The rollout targets Windows desktop and explicitly excludes Firefox MSIX/Microsoft Store builds because of packaging and integration differences. Enterprises that push the Store package will not see parity. (connect.mozilla.org)
• Not a 1:1 PWA replacement: Service worker and background behavior may diverge from Chromium‑based PWAs — developers and admins should not assume feature parity.
• Early QA issues reported: Community testers have flagged duplication of taskbar icons, pin/unpin oddities and other teething problems during early rollouts; expect these to be smoothed across subsequent point releases. (connect.mozilla.org)

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Microsoft Copilot in the AI sidebar — convenience, not local processing​

Integration model​

Firefox’s AI sidebar is designed as a provider switchboard: users can choose an AI provider (ChatGPT, Gemini, Claude and now Copilot) and the browser opens that provider’s web interface inside the sidebar panel. This is a web‑UI integration, not a local embedding of Microsoft’s Copilot engine inside Firefox. Conversations and any uploads are processed by Microsoft servers under Microsoft’s terms. (ghacks.net)

Practical user experience​

• Copilot is selectable in the sidebar and provides summarization, text generation, voice and multimodal inputs depending on account entitlements.
• The sidebar includes quick actions for page summarization and right‑click context menu access for Copilot features in some builds. (ghacks.net)

Privacy and governance implications​

• Data leaves the device: Using Copilot via the sidebar entails sending prompts and uploads to Microsoft’s cloud. Organizations must treat this like any other SaaS AI service when drafting data handling policies.
• Opt‑out controls exist: Users and admins can remove the AI provider from the sidebar or disable AI features via about:config keys (preferences beginning with browser.ml.*). For managed environments, enterprise policies and Group Policy/MDM should be evaluated before broad enablement.

Risk vs benefit​

The convenience of a sidebar quick‑access to Copilot is real for productivity tasks. However, because the integration is effectively a hosted web app, it does not materially change the underlying privacy trade‑offs versus using Copilot in a separate browser tab or in Edge. For regulated environments, the question is not technical feasibility but policy: will employees be permitted to paste, upload or summarize sensitive content through a third‑party model?

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Privacy hardening: Fingerprinting Protection and Private‑mode downloads​

Expanded fingerprinting protections​

Firefox 143 extends its anti‑fingerprinting work by returning constant or normalized values for additional system attributes. That reduces the entropy available to trackers in building a unique client fingerprint and is part of Mozilla’s layered approach that includes tracker blocking and ETP strict modes. This is meaningful progress, though not a complete solution to the fingerprinting arms race. (firefox.com)

Private Browsing download behavior​

• Downloads initiated in Private Browsing now trigger an on‑screen prompt offering to keep the file or delete it automatically when all private windows are closed.
• The setting “Delete files downloaded in private browsing when all private windows are closed” is available under Settings > General > Files and Applications and is disabled by default. (firefox.com)

This small UX change reduces the chance of leaving transient downloads on disk by accident — a useful privacy quality‑of‑life feature for users who treat Private Browsing as a guaranteed ephemeral workspace.

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Accessibility and platform support​

Windows UI Automation​

Firefox 143 updates Windows UI Automation hooks to improve interoperability with assistive technologies such as Narrator, Voice Access and Text Cursor Indicator. The improvements expose better role, state and name information and resolve several historical mismatches that affected screen reader and voice control workflows. These changes are important for compliance and real usability among assistive‑tech users.

Media codec parity: xHE‑AAC​

xHE‑AAC support arrives on Windows 11 (22H2+), macOS and Android 9+, helping with modern low‑bitrate audio streaming use cases and broader compatibility across streaming services that are moving to newer codecs. Note that platform decoders or OS codec availability still matter for some devices. (firefox.com)

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Mobile changes: Android and iOS notes​

• Android: DNS over HTTPS (DoH) can now be configured from the Firefox settings UI. The Android download manager also gets “Smarter downloads” with real‑time progress and quick controls. These are practical privacy and usability gains on mobile. (firefox.com)
• iOS: Firefox for iOS received a UI refresh and a new “Shake to Summarize” gesture that invokes page summarization when the device is shaken; this requires iOS 26 or later. This feature leans on the browser’s summarization tooling and the iOS motion APIs.

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Address bar “Important dates” — helpful or noisy?​

Firefox 143 introduces region‑targeted urlbar suggestions that surface upcoming important dates (examples: Mother’s Day) for users in certain locales. The feature is controlled by an about:config preference (browser.urlbar.suggest.importantDates) and a feature gate, so administrators and advanced users can disable it. Because the urlbar is already heavily used for history/bookmarks and quick actions, the UX risk is that added suggestions could push more relevant results out of view; Mozilla appears to be gating this feature by region and rollout flags to mitigate that.
A practical recommendation: users who prefer a minimal urlbar should set browser.urlbar.suggest.importantDates to false in about:config where available.

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Developer and standards updates​

Firefox 143 includes several modest but important web‑platform improvements:

• Updated Grid sizing algorithm to align more closely with the CSS Grid specification, fixing percentage‑row and aspect‑ratio layout corner cases.
• <input type="color"> now accepts the CSS color() notation and named colors (values normalize back to hex).
• ::details-content pseudo‑element is enabled, allowing better styling of <details> contents.
• New add‑on API helper storage.StorageArea.getKeys() for extension authors. (developer.mozilla.org)

These developer‑facing changes help reduce cross‑browser layout surprises and improve debugging ergonomics for web apps that depend on CSS Grid and modern color formats.

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Security fixes and ESR details — what we can verify​

Mozilla’s release notes for the 143 branch indicate security fixes are included in the update. At the time of publication, Mozilla’s MFSA (Mozilla Foundation Security Advisories) pages are current up through the 142 release family and several CVEs were tracked to the 140–142 cycle; the full MFSA enumeration for 143 may be published shortly after the release notes are posted. Administrators should monitor Mozilla’s MFSA list and their vulnerability feeds and apply the ESR builds or update channels as appropriate. If a specific MFSA link yields a 404, that typically means the advisory is still being prepared or the MFSA index lags the product release; check again after a short delay and rely on vendor security advisories for CVE details. (mozilla.org)
Enterprise customers should plan to validate Firefox 143 and the corresponding ESR builds (Firefox ESR 140.x / 115.x branches as relevant) against their extension inventory and managed policies before mass rollout. The Firefox for Enterprise notes and ESR guidance remain the authoritative path for controlled deployment. (support.mozilla.org)

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Practical management: enable, disable, and policy controls​

For end users and IT administrators who want to test or control the new surfaces, here are concrete steps:

• To try pinned web apps (Windows desktop):
• Go to aboutreferences#experimental (Firefox Labs) and toggle “Add sites to your taskbar” or set browser.taskbarTabs.enabled to true in about:config. Restart Firefox to apply. (connect.mozilla.org)
• To disable the AI sidebar or Copilot:
• Remove the AI panel from the sidebar UI, or open about:config and set browser.ml.enable, browser.ml.chat.enabled, browser.ml.chat.menu and related browser.ml.* prefs to false. For enterprise‑grade controls, evaluate Mozilla’s enterprise policies and Group Policy templates. (ghacks.net)
• To turn off “Important dates” suggestions:
• In about:config set browser.urlbar.suggest.importantDates to false if present in your build.
• To auto‑delete Private Browsing downloads:
• Settings > General > Files and Applications → toggle “Delete files downloaded in private browsing when all private windows are closed.” The prompt will also appear when downloading in private sessions. (firefox.com)
• For enterprise deployment:
• Test the non‑Store installer path if you need pinned‑site behavior; the Microsoft Store package is excluded from this capability. Audit third‑party AI use and enforce acceptable use policies before enabling Copilot for workstations.

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Critical analysis — strengths, trade‑offs and risks​

Strengths​

• Practical parity: Firefox 143 closes concrete UX gaps compared with Chromium browsers by delivering taskbar‑pinned web apps, improved media codec support and refined mobile privacy options. These are features users expect in 2025.
• Privacy‑minded defaults where it counts: Fingerprinting protections and the opt‑in nature of the AI sidebar let Mozilla keep a privacy posture while still offering modern conveniences. (firefox.com)
• Accessibility improvements: Windows UI Automation updates are a concrete win for assistive tech users and enterprises with accessibility requirements.

Trade‑offs and risks​

• Third‑party AI surface: Crowding Copilot and other cloud assistants into the browser UI increases the chance users will inadvertently send sensitive data to cloud services. The integration is a web surface—convenient, but governed by provider terms. Organizations must treat it as a cloud SaaS and apply governance accordingly.
• Fragmented rollout & packaging differences: The Microsoft Store/MSIX exclusion for pinned web apps introduces deployment complexity for organizations that standardize on Store installs. Rollout flags and progressive releases can also complicate helpdesk documentation.
• Fingerprinting is incremental, not absolute: Constant‑value normalization reduces entropy but doesn’t eliminate fingerprinting; dedicated adversaries can combine signals across vectors. Users seeking robust anonymity should layer additional protections (Tor, strict ETP, containers).

Unverifiable or evolving claims (flagged)​

• The precise source and refresh cadence for the address‑bar “important dates” enrichment is not fully documented publicly; the feature is region‑gated and controlled with preferences that may vary across builds. Administrators and users should treat rollout behavior as subject to change.
• If a published security advisory link returns a 404 immediately after release, it usually means the MFSA page is pending; always cross‑check MFSA listings and vendor advisories an hour or two after the product release before assuming a missing advisory. (mozilla.org)

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Bottom line and guidance​

Firefox 143 is an incremental but meaningful release that focuses on closing practical gaps for Windows users while carefully exposing AI capabilities as optional, provider‑selectable tools. For individual users the headline features—pinned web apps, camera preview, smarter private‑mode downloads—are straightforward quality‑of‑life improvements. For enterprise admins, the presence of Copilot in the sidebar and install‑channel differences require testing, updated policy guidance and possibly configuration to control AI access.
Recommendations:

• Power users on Windows: test pinned web apps on a non‑Store install and validate extension behavior for your critical sites. (ghacks.net)
• Privacy‑sensitive users: keep fingerprinting protection enabled, disable browser.ml.* prefs to remove AI features, and enable auto‑delete for private downloads if you rely on ephemeral files. (firefox.com)
• IT teams: pilot Firefox 143 and the matching ESR builds in a controlled group; confirm whether your environment uses Store‑installed Firefox (which lacks pinned web‑app support) and update help desk documentation to reflect the new AI and web‑app surfaces. Monitor MFSA advisories and patch paths for CVEs tied to the release. (support.mozilla.org)

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Firefox’s journey through the 140s demonstrates a pragmatic balancing act: catch up on platform features users expect while attempting to retain the choice and privacy that differentiate Firefox. The introduction of pinned web apps and the AI sidebar with Copilot moves the browser closer to modern expectations; the important questions now are governance, test coverage and whether Mozilla can keep rollout friction low while preserving the controls required by privacy‑conscious users and enterprises. (developer.mozilla.org)
Conclusion: Firefox 143 is worth testing for nearly every Windows user and essential reading for administrators — but treat Copilot and other third‑party assistants as cloud services, not local features, and plan your rollout accordingly.

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Source: gHacks Technology News Mozilla Firefox 143.0 adds support for Progressive Web Apps, Copilot on sidebar, Important dates in the address bar - gHacks Tech News