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