Firefox Nightly Expands AI with Copilot in Sidebar and New Tab Widgets

Firefox Nightly has quietly added Microsoft Copilot to its sidebar and rolled out early New Tab page widgets — a clear sign that Mozilla is expanding both its AI integrations and its on-page productivity ambitions, all inside the experimental Nightly channel where features are prototyped before (maybe) arriving in Beta and Release. (ghacks.net, windowsreport.com)

Background​

Mozilla has used Firefox Nightly for years as the public testbed for new features, design experiments, and platform changes. Nightly builds are updated daily and are explicitly intended for testers and contributors willing to tolerate instability in exchange for early access. That is where Mozilla’s recent AI experiments — a sidebar chatbot framework that supports multiple providers — have been evolving. (wiki.mozilla.org, lifewire.com)
At the same time, Mozilla has been beefing up the Firefox New Tab page with “Labs” experiments: wallpapers, story cards, and now productivity widgets such as Lists (to-do) and Timer. These widgets are currently surfaced through Firefox Labs and are being rolled out in limited tests as Mozilla gathers feedback. (support.mozilla.org, connect.mozilla.org)
This article summarizes the changes, verifies what is currently in Nightly, analyzes the practical implications for everyday users and IT power users, and flags the privacy, security, and product-design trade-offs to watch as Mozilla proceeds.

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What’s new in Firefox Nightly right now​

Microsoft Copilot in the sidebar​

• Microsoft Copilot has been added as a provider option inside Firefox Nightly’s chatbot sidebar. Users who test Nightly can choose Copilot alongside other providers such as ChatGPT, Google Gemini, Anthropic Claude, and various community-hosted models. Reports describe Copilot appearing as another selectable sidebar entry, able to accept text, images, and voice input for generating replies, summaries, and other responses. (ghacks.net, windowsreport.com)
• Early coverage indicates Copilot in the sidebar exposes the kinds of interaction modes Copilot offers elsewhere (e.g., quick versus deeper responses, image/document analysis, voice) though some of those implementation details may differ or be limited in Nightly compared with Microsoft’s first-party integrations. Some outlets describe “Quick Response”, “Think Deeper”, and “Smart” modes inside the sidebar version of Copilot. These reports come from early testers and site previews; Mozilla has not published a formal Copilot-specific spec for Nightly at the time of reporting. (ghacks.net, windowsreport.com)

New Tab page productivity widgets (Lists and Timer)​

• Firefox Labs is testing built-in Lists (task/to‑do lists) and a Timer widget, surfaced on the New Tab page between shortcuts and recommended stories where available. The widgets are simple, local-first (no sync currently), and intentionally minimal in this early experiment: up to 10 lists, up to 100 items per list, and no built-in cloud sync as of the initial rollout. Mozilla is explicitly soliciting feedback. (support.mozilla.org, connect.mozilla.org)
• The Labs documentation and support pages explain basic usage (add items, check them off, set timers) and emphasize that the features are experimental and device-local for now. That means lists are lost with profile removal unless users copy them out manually. (support.mozilla.org)

JPEG XL toggle in Firefox Labs​

• Nightly also exposes a Labs toggle for JPEG XL (image/jxl) support — an in-development image format intended to be more efficient than legacy JPEG and to support features such as lossless transcodes, alpha channels, and HDR. Mozilla has historically treated JPEG XL as experimental and has cited implementation complexity, security considerations, and dependency on safe decoders as reasons for cautious rollout; the Nightly Labs control surfaces that capability for testers. (phoronix.com, reddit.com)

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Why these moves matter for Firefox users​

Choice and competition in the browser AI race​

Adding Copilot to the list of chat providers is a strategic move to keep Firefox competitive with other browsers that embed first-party AI (for example, Edge with Copilot and Chrome with first-party Gemini integrations). By making the sidebar a multi-provider surface, Mozilla is pursuing a model of user choice: let the user pick which chatbot service they prefer rather than shipping a single default that locks users into one vendor. That aligns with Mozilla’s public messaging about user agency, though the practical trade-offs are more complex. (lifewire.com)

Productivity features that rethink New Tab​

The New Tab page is shifting from a speed-dial to a more utility-focused surface. Widgets such as Lists and Timer are small, admittedly modest additions, but they reveal a product direction: Mozilla sees the real estate of a user's New Tab as valuable — both for improving the browsing experience and for creating new engagement hooks (and potentially new referral or ad surfaces down the road). The Labs rollout keeps everything optional and experimental, but the product signal is clear. (connect.mozilla.org)

JPEG XL: performance and web adoption implications​

If Firefox stabilizes JPEG XL support, web developers and image-serving platforms could eventually reduce bandwidth and storage costs by adopting a more efficient format. That said, browser support across the ecosystem matters more than a single vendor’s implementation; until Chrome, Safari, and other major engines converge on a format, adoption will be incremental and mixed. Mozilla’s experimental approach here is pragmatic: expose it to Nightly users, test decoder safety and compatibility, and iterate. (phoronix.com, reddit.com)

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Critical analysis — strengths and opportunities​

1) User choice and extensibility​

• Strength: A sandboxed, extensible sidebar that can accommodate multiple AI providers gives users flexibility and avoids vendor lock-in. It also enables power users and organizations to configure on‑device or self-hosted models (where supported) for greater privacy. This multi-provider approach is one of the clearest strengths in Mozilla’s design thinking for AI in Firefox. (lifewire.com)
• Opportunity: Mozilla can further differentiate by promoting on-device models or first-class local-only options, something privacy‑conscious users and enterprises will value over cloud-bound chatbots.

2) Incremental features that reduce friction​

• Strength: Small New Tab widgets like Lists and Timer are unobtrusive productivity helpers that, if executed well, can reduce friction and keep the core browsing experience focused. Their local-first design for the initial experiment reduces privacy risks while still enabling useful interactions. (support.mozilla.org)
• Opportunity: If Mozilla adds opt-in sync (with clear encryption and privacy guarantees) and integrates with existing product ecosystems (calendars, reminders), these widgets could become genuinely helpful without becoming attention-hijacking.

3) Technical caution on image formats and security​

• Strength: Mozilla’s conservative, test-driven approach to JPEG XL — focusing on a safe decoder and incremental rollout — is appropriate for a browser engine where bad decoders can be an attack surface. Prioritizing safety and conformance is the right move, even if it slows adoption. (phoronix.com)

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Risks, trade-offs, and unanswered questions​

1) Privacy and data-sharing with third-party chatbots​

• Risk: The most immediate concern is that integrating third-party chatbots in the browser sidebar means more user-generated content will be routed to external servers (OpenAI, Microsoft, Google, Anthropic, etc.). Even if Mozilla positions the feature as optional, the UI prominence of a sidebar chatbot and page-context summarization actions could nudge users toward sending content they did not intend to share. This increases exposure to data collection policies, retention practices, and the possibility of model training on user inputs depending on the provider’s terms. Early reports and community discussions show users worrying about exactly this. (lifewire.com, reddit.com)
• Mitigation: Mozilla can and should require clear, per-provider privacy disclosures, explicit opt-in, and a default-off stance — plus local warnings when a user triggers a summarization or sends page content to a remote model.

2) Security and stability of Nightly builds​

• Risk: Nightly builds intentionally include experimental code and daily updates; that is, these features are not production-ready. Users who install Nightly to try Copilot or widgets may experience crashes, regressions, or security bugs. Numerous community threads remind users not to run Nightly as their only browser if they cannot tolerate breakages. (wiki.mozilla.org, reddit.com)
• Mitigation: Mozilla should maintain clear onboarding text for Nightly users and isolate risky experiments via pref flags and about:config toggles that can be quickly reverted.

3) UI clutter and attention economy concerns​

• Risk: Expanding the New Tab page into a hub of widgets, stories, search chips, and trending terms risks transforming an otherwise neutral entry point into a distraction portal. Critics argue that the New Tab page should remain clean and fast rather than becoming a launching pad for external content or referral traffic. The tension is between product monetization/user engagement and a clean, user-controlled browsing experience. (connect.mozilla.org)
• Mitigation: Give users granular control to disable widgets, hide story cards, and select minimalist modes. Preserve a “Zen” or minimal New Tab option for users who want nothing more than an address bar and frequently visited tiles.

4) Dependence on vendors and compatibility hurdles​

• Risk: Third-party services change APIs, behaviors, or uptime characteristics. Microsoft’s Copilot, for instance, is first optimized for Edge and the Microsoft ecosystem; embedding a Copilot experience inside Firefox will likely require ongoing compatibility maintenance. Microsoft’s own Copilot web interfaces have shown sporadic issues in Firefox in community reports, and behavior differences between browsers may surface. Those compatibility issues could degrade the user experience or create inconsistent behaviors in Firefox’s sidebar. (learn.microsoft.com)
• Mitigation: Mozilla should treat third-party providers as optional integrations and provide fallback experiences (e.g., opening provider web pages, graceful error messages) rather than brittle in‑sidebar embeds that can fail without recourse.

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Practical guidance for testers and IT pros​

• If you want to try Copilot in Firefox Nightly:
• Install Firefox Nightly from Mozilla’s Nightly download pages and use it as a secondary browser for testing. Nightly builds are available for Windows, macOS, and Linux. (wiki.mozilla.org, blog.nightly.mozilla.org)
• Enable the AI Chatbot Integration via Nightly Experiments or the relevant Firefox Labs toggles. For advanced toggling you can use about:config prefs like the reported browser.ml.* flags (exercise caution). (lifewire.com, reddit.com)
• If you want to test the New Tab widgets:
• Look for Firefox Labs (New Tab widgets) in Nightly or Beta channels — the Lists and Timer widgets are currently being tested and are device-local by design. Copy lists to the clipboard if you want backups; there’s no sync in the initial rollout. (support.mozilla.org, connect.mozilla.org)
• If you care about image compatibility:
• Treat JPEG XL support in Nightly as experimental. Web developers should continue to serve fallback image formats and only enable image/jxl where users’ browsers clearly indicate support. Mozilla’s cautious approach means behavior may vary across Nightly builds until a safe, fully integrated decoder lands. (phoronix.com, reddit.com)
• If you operate organizationally:
• Keep AI features off by policy for managed deployments until their privacy/retention terms are fully vetted. Firefox exposes prefs for disabling browser.ml* features; managed policies can also lock settings for fleets to prevent accidental data leakage. Community reporting and Microsoft Q&A threads indicate Copilot web apps occasionally behave differently in Firefox, adding another reason for conservative rollouts in enterprises. (reddit.com, learn.microsoft.com)

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Verification notes and cautionary flags​

• Several public tech sites and testing reports confirm Copilot’s presence in Nightly sidebars at the time of this writing, but the exact feature set and available modes (for example, claims that a “Smart” mode leverages GPT‑5) come primarily from hands-on test reporting and site previews rather than a single authoritative Mozilla spec. Those implementation details should be treated as early tester reports rather than finalized product claims. Readers should treat mode names and underlying model labels as provisional until Mozilla or Microsoft publish formal documentation. (ghacks.net, windowsreport.com)
• The New Tab widgets and the Labs JPEG XL toggle are documented on Mozilla support and community channels as experiments available via Nightly (and in some cases Beta regions). Mozilla’s own support pages outline limitations (no sync, local-only storage) and the Labs initiative for gathering feedback; these are authoritative confirmations that the features are experimental and optional. (support.mozilla.org, connect.mozilla.org)
• Community reports (forums, Reddit, Microsoft Q&A) indicate intermittent compatibility and load issues when third-party Copilot interfaces are used inside Firefox. Those reports are actionable signals that real-world behavior can vary; they are important corroboration but not a substitute for formal bug tracker entries or Microsoft statements. Where community claims describe behavior, they are flagged here as community observations. (learn.microsoft.com)

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What to watch next​

• Will Mozilla offer robust local-only on-device models or a clear way for users to run self-hosted LLMs inside the sidebar? That would be a game-changer for privacy-oriented users and organizations.
• Will Mozilla introduce opt-in encrypted sync for New Tab Lists so users can safely carry lightweight task data between devices without sending it to third-party clouds?
• How will Mozilla handle monetization pressure on the New Tab real estate? A user-controlled, minimal New Tab option will be essential to retain privacy-focused users.
• Will Copilot in Firefox eventually expose the same feature parity as Edge, or will Microsoft limit some capabilities to its own browser for competitive reasons? Compatibility issues reported in Microsoft Q&A suggest this is an open engineering and policy question. (learn.microsoft.com)

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Final assessment​

Mozilla’s Nightly additions are a pragmatic blend of experimentation and product realignment. Adding Microsoft Copilot as a selectable sidebar provider demonstrates that Firefox intends to be a neutral platform for AI services rather than shipping a single vendor-first assistant. The New Tab widgets reveal a product strategy that views the New Tab page as useful real estate for convenience features and user workflows.
Those moves bring real user benefits: choice, convenience, and early access to web-tech improvements like JPEG XL. They also bring risks: increased surface area for data sharing with third parties, potential UI clutter and distraction, and the well-known instability of Nightly builds.
For cautious users and IT administrators the sensible path is to treat Nightly as a testing ground: try the features in an isolated profile or secondary install, verify provider privacy terms before sending sensitive content to cloud models, and use Firefox’s Labs/prefs to disable any experiments you don’t want. For Mozilla, the challenge will be to balance experimentation and engagement with clear, enforceable privacy and UX boundaries — because the real test will not be whether Copilot can be placed in a sidebar, but whether Mozilla can keep the browser useful, fast, and under the user’s control as it navigates the AI era.

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Source: OMG! Ubuntu Firefox Adds CoPilot Chatbot, New Tab Widgets in Nightly Builds - OMG! Ubuntu