Firefox 143: Windows taskbar PWA pins, Copilot sidebar, privacy & UX boosts

Mozilla’s Firefox 143 lands as a pragmatic, Windows‑focused update that finally closes several long‑standing feature gaps while introducing new privacy, accessibility, and media improvements — notably taskbar‑pinned web apps (PWA‑style), Microsoft Copilot in the AI sidebar, camera preview in permission dialogs, and address‑bar “important dates” suggestions — but those conveniences come with rollout caveats and governance questions that deserve careful attention.

Background / Overview​

Firefox’s 143 cycle continues Mozilla’s pattern of iterative releases that combine developer‑facing platform fixes with visible user‑experience changes. The release is notable because it brings features that many users have expected from Chromium browsers — single‑site app/taskbar pinning, richer media codec support, and direct in‑browser access to commercial AI assistants — while doubling down on fingerprinting protections and accessibility improvements. The 143 branch shipped across channels on the scheduled cadence and is documented in developer pages, enterprise notes, and community reporting. (developer.mozilla.org)
This feature set reflects two parallel priorities: closing functional parity gaps with other browsers (Windows taskbar apps, xHE‑AAC playback) and offering optional, user‑selectable integrations with third‑party services (AI providers in the sidebar). For Windows power users and organizations, that mix delivers clear productivity wins but also introduces policy and compatibility questions — especially where install channels or regional rollouts limit availability.

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What’s new in Firefox 143 — the short list​

• Progressive Web App / taskbar pinning on Windows: pin sites to the taskbar and launch them in simplified windows that still retain extensions and profile context. Not available for Firefox builds installed from the Microsoft Store.
• Microsoft Copilot in the AI/sidebar: Copilot is now one selectable provider inside Firefox’s AI chat sidebar alongside other chat providers. This is a web‑surface integration that opens the provider’s web UI in the panel. (windowsreport.com)
• Address‑bar “important dates”: the urlbar can surface culturally relevant upcoming dates (for example, Mother’s Day) in selected regions; controlled by rollout flags and about:config preferences.
• Camera preview in permission dialog: when a site requests camera access, Firefox shows a live preview inside the permission prompt — handy for machines with multiple cameras.
• Private‑browsing download options: downloads in Private Browsing trigger a prompt offering to keep or auto‑delete downloaded files; there’s an opt‑out/in Setting to control auto‑delete behavior.
• Enhanced Fingerprinting Protection: Firefox reports constant values for additional system attributes to reduce fingerprinting entropy.
• Windows UI Automation improvements: better support for assistive technologies (Narrator, Voice Access, Text Cursor Indicator) through updated UI Automation bindings.
• xHE‑AAC playback: Firefox 143 adds support for xHE‑AAC audio playback on Windows 11 (22H2+), macOS, and Android 9+. Bug and platform tracking show the codec landing on the 143 milestone. (bugzilla.mozilla.org)
• Android: DNS over HTTPS UI support and “Smarter downloads.” iOS: redesigned UI plus Shake to Summarize (requires iOS 26 or later). These are platform‑specific enhancements in the 143 cycle.

Each of these items is rolling out with caveats: some features are gated by region, some require the classic desktop installer rather than the Microsoft Store package, and others remain behind experiments or flags for progressive rollout. Administrators and power users should not assume universal availability immediately after upgrading.

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Progressive Web Apps on Windows — practical details and limits​

What Mozilla shipped​

Firefox 143 introduces a Windows‑focused “web apps” workflow: users can add or pin a website to the Windows taskbar and open it in a simplified Firefox window. Unlike many Chromium SSBs that strip extensions or sign‑in state, Firefox’s implementation intentionally preserves access to your extensions and profile context, meaning password managers and privacy add‑ons continue to work inside these app windows.

How it behaves​

• A new “Add to taskbar” / “Install site as app” control appears in the address bar or menu when the feature is available.
• Confirming the action creates a simplified, pinned window with the site’s icon in the Windows taskbar.
• The window is a browser‑hosted container rather than a full OS‑registered PWA; certain deep OS integrations may differ from Chromium PWAs (notifications, background workers, etc.).

Important limitations​

• The feature is currently Windows‑only and explicitly excluded from the Microsoft Store / MSIX build because of packaging and store integration differences; organizations deploying the Store package will not receive this capability until/if that changes.
• It is not a complete, standards‑level PWA registration; developers should not assume parity with Chromium PWA behaviors.
• Early testers reported minor UI oddities (duplicate taskbar icons, pin/unpin edge cases); these are being tracked and will likely be addressed in follow‑on point releases.

Why it matters​

For users who run web services as near‑desktop apps (Gmail, Slack, web dashboards), pinned web apps reduce tab clutter and improve workflow speed. The preservation of extensions inside these windows is a meaningful differentiator for privacy and productivity tooling. For IT, however, install‑channel fragmentation means you must test the installer you plan to distribute before adopting the feature organization‑wide.

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Copilot in the sidebar — convenience, architecture, and privacy trade‑offs​

What changed​

Firefox’s AI sidebar has been extended to include Microsoft Copilot as a selectable provider. The sidebar is designed to host multiple third‑party chat providers (ChatGPT, Google Gemini, Anthropic Claude, Copilot, etc.), and selecting a provider opens that provider’s web interface inside the panel. This is a web‑UI integration rather than an on‑device implementation of Microsoft’s models. (windowsreport.com)

Key technical points​

• The sidebar is a convenience container: conversations, uploads, and prompts are processed by the provider’s servers under the provider’s terms.
• Some functionality (like account‑entitlement features, personalization, or extended context) depends on the user’s Microsoft account and subscription state.
• Mozilla provides preferences and about:config toggles to disable AI sidebar features; enterprises can use policies and configuration to control availability.

Practical controls​

• Remove the AI panel via the Sidebar UI if you don’t want quick access.
• For deeper control, set these about:config preferences to false: browser.ml.enable, browser.ml.chat.enabled, browser.ml.chat.menu, browser.ml.chat.page (pref names vary by channel and build).

Privacy and governance considerations​

Bringing Copilot (or any cloud assistant) into the browser UI increases the risk that users will transmit sensitive content to third‑party services — intentionally or accidentally. Organizations should:

• Treat Copilot as a SaaS endpoint when evaluating compliance.
• Restrict use where PII, regulated data, or IP may be entered into the chat.
• Train users and apply conditional access or policy controls where needed.

What to watch (unverified claims flagged)​

Some early hands‑on reports describe “modes” (Quick Response, Think Deeper, Smart) and claim backend model names (for example, Smart using GPT‑5). These details come from early tester write‑ups and community previews and should be treated as provisional until confirmed by Microsoft or Mozilla’s formal documentation. Flagging these as unverified is prudent.

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Address bar: “Important dates” — UX, rollout, and how to disable it​

Firefox 143 can surface upcoming culturally relevant dates (for example, Mother’s Day) directly in the address‑bar suggestion list. The feature is region‑gated and appears for a limited set of locales; it is controlled by internal prefs such as browser.urlbar.suggest.importantDates and a related featureGate pref. Where the pref exists, users can toggle it from about:config to remove the enrichment.
Why this matters: the urlbar is now a micro‑productivity surface; the new enrichment is useful for quick reminders but raises privacy and noise concerns for users who prefer minimal suggestions. Organizations wanting a minimal address bar should set browser.urlbar.suggest.importantDates to false where available.

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Camera preview, private‑mode download behavior, and fingerprinting protections​

• Camera preview: When a website requests camera access, Firefox now shows a live preview in the permission dialog so users can confirm which camera the site will use. This small but thoughtful UX change helps multi‑camera setups (laptops + USB webcams).
• Private‑browsing downloads: Downloading while in Private Browsing now presents a prompt letting users keep the file or let Firefox delete it automatically when the last private window closes. The auto‑delete option is off by default and configurable under Settings → General → Files and Applications.
• Fingerprinting Protection: Firefox 143 expands the set of system attributes normalized to constant values, making trackers’ fingerprints less unique. This is an incremental improvement in the wider fingerprinting arms race and should be considered one defensive layer among several.

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Accessibility and platform parity​

Firefox 143 rolls out improved Windows UI Automation bindings, which improve compatibility with assistive technologies such as Narrator, Voice Access, and Text Cursor Indicator. These improvements are a concrete gain for users relying on screen readers and voice control, and they reflect Mozilla’s continued focus on accessibility parity. Administrators who test assistive workflows should validate 143 against their specific screen‑reader stacks.
On media parity, xHE‑AAC playback support was tracked into the 143 milestone in Mozilla’s bug tracker and the patching process, adding decoder availability on Windows 11 (22H2+), macOS, and Android 9+. That matters for streaming providers and users who rely on improved low‑bitrate audio behavior. The codec’s integration has been an open bug for years and is now reported fixed for the 143 branch. (bugzilla.mozilla.org)

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Android and iOS: updates worth noting​

• Android: Firefox 143 adds UI preference controls for DNS over HTTPS (DoH) and introduces “Smarter downloads” — a real‑time download manager with quick controls and tracking. DoH UI support is a useful privacy and manageability option for mobile users.
• iOS: The iOS build gets a redesigned UI and a Shake to Summarize feature that shows a page summary when the user shakes their iPhone; this feature requires iOS 26 or later. Expect gradual rollout and regional differences.

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Security fixes, ESR and enterprise notes​

Mozilla states that Firefox 143 ships with security fixes; enterprise release notes and ESR updates accompany the stable release. If a published security advisory initially returns a 404, that typically means the MFSA page is still being prepared and will appear shortly — administrators should monitor Mozilla’s MFSA listings and their vulnerability feeds for CVE details. Firefox for Enterprise support pages and MDN developer release pages document the branch and developer changes for IT planning. (support.mozilla.org) (developer.mozilla.org)
ESR updates: Firefox ESR branches corresponding to this cycle (140.x and the continued 115.x line) are available for enterprise deployment; check the ESR notes and test extensions and policies before mass rollout. Packaging differences (classic installer vs Microsoft Store) are particularly relevant for pinned web‑apps availability.

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How to enable, disable, or manage the headline features (practical steps)​

• To pin a site to the Windows taskbar (when available):
• Visit the site, open the address‑bar menu or look for an “Add to taskbar” / “Install site as app” control.
• Confirm the install and choose “Open as window” or equivalent.
• The site will appear as a simplified window with its own taskbar icon.
• To disable Copilot / AI sidebar:
• Remove the AI panel via 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. Enterprise policy controls can also be used for fleet management.
• To turn off “Important dates” in the urlbar:
• Open about:config and set browser.urlbar.suggest.importantDates to false, if present in your build. Note that this pref may be rollout‑gated and not exist in every installation.
• To enable auto‑delete of Private Browsing downloads:
• Settings → General → Files and Applications → toggle “Delete files downloaded in private browsing when all private windows are closed.” The prompt appears when downloading in private sessions; the toggle controls auto‑delete behavior.
• To test xHE‑AAC playback:
• Ensure your platform matches the stated requirement (Windows 11 22H2+, macOS, or Android 9+).
• Try playback of a known xHE‑AAC stream or media sample; track behavior and file a report if a stream fails to decode. Bug tracking shows the decoder landed in the 143 milestone. (bugzilla.mozilla.org)

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Critical analysis — strengths, trade‑offs, and risks​

Strengths​

• Practical parity: Firefox 143 addresses real user needs by restoring taskbar pinned web apps and platform media compatibility, reducing the everyday convenience gap with Chromium browsers.
• Choice and opt‑out: Mozilla’s design keeps AI features optional and provider‑selectable; users can remove the sidebar or disable ML prefs entirely. That preserves user choice and avoids a single‑vendor lock‑in.
• Accessibility wins: Windows UI Automation improvements are meaningful for assistive tech users and enterprise accessibility compliance.

Trade‑offs and risks​

• Third‑party AI data flows: Copilot (and other providers) processes your chat content on their servers. For regulated environments, that raises compliance, retention, and data‑loss concerns that must be managed with policies and training.
• Rollout fragmentation: Feature availability differs by region, install channel, and progressive rollout flags. Organizations should test the exact build and installer they plan to deploy.
• Fingerprinting is incremental: Constant‑value normalization helps but is not a silver bullet. Adversaries can still combine signals across vectors; users seeking anonymity should layer protections (Tor, strict ETP, containers).
• Cosmetic vs integrated AI: Packaging a provider’s web UI into a sidebar is convenient but is not the same as a deeply integrated assistant with automatic page context access — expectations must be managed, and claims of deeper model access should be vetted. Early reports of model names or enhanced modes should be treated as provisional unless confirmed by vendor documentation.

Enterprise guidance (practical)​

• Test before deploy: Validate extensions, assistive tech, and policies against Firefox 143 (classic installer and Store package) in a staging environment.
• Lock or disable AI features for regulated users until data‑handling terms and access controls are accepted by legal/compliance teams.
• Update helpdesk documentation to reflect address‑bar and private‑download UX behavior changes to reduce support noise.

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Final verdict — who should upgrade and when​

Firefox 143 is a pragmatic, user‑centric update that will appeal most to Windows power users, privacy‑conscious individuals who value stronger fingerprinting protections, and organizations that want parity on media codecs and accessibility. The PWA‑style taskbar pinning is a useful productivity add; Copilot in the sidebar gives users an easy way to access AI assistants — provided those users and their organizations accept the third‑party data‑handling implications.
For enterprises and privacy‑sensitive deployments, the sensible path is cautious: test the build, evaluate the Store vs classic installer implications, and apply policy controls or disable AI features for cohorts where data exposure is a concern. Users who prefer a minimal, less enriched address bar or tighter privacy defaults should check and toggle the related about:config prefs after upgrade.
Overall, Firefox 143 nudges the browser forward in meaningful, iterative ways: it brings convenience without removing control, and it asks administrators and privacy teams to do the same — balance the productivity gains against governance responsibilities and test before wide rollout.

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Conclusion
Firefox 143 is a practical release that closes specific functional gaps and adds thoughtful UX and privacy improvements. The Windows‑only taskbar apps and Copilot sidebar headline the release, but deployment details — install channel differences, region gating, and enterprise policies — determine whether those headlines translate into immediate, organization‑wide value. The release reiterates a central truth for modern browser management: convenience and control can coexist, but only when technical teams pair feature adoption with clear policy and user education.

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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