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December 9, 2025

6.6.6 - Privacy hardening

A (not so) devilish release 👹

Info

A few privacy‑sensitive behaviours from upstream Firefox code were not fully disabled in earlier Waterfox builds as we intended. In particular:

  • Region detection could still make a one‑time geo‑IP request to Mozilla’s privacy‑preserving backend to infer your country on first run.
  • Some local ML/AI plumbing was still technically available and, in edge cases, could surface onboarding UI (e.g. AI link previews) even though the actual AI features and settings stayed disabled.

These weren’t aligned with Waterfox’s privacy goals. We should have caught them earlier, and we appreciate the community for surfacing them so we could tighten things up.

This release makes those behaviours explicit and turns them off by default.

Various fixes

  • Private Tab will now use your default selected private search.
    • The context menu search while in private tab will also open a new private tab instead of normal tab.
  • Fixed an issue where the Bookmarks widget in the status bar would not open submenus, so now all bookmark folders now work correctly when the button is pinned to the status bar.
  • Fixed a minor issue where the “Status Bar” entry in the Toolbars menu would output internal errors to the browser console.
  • Cookie banner handling no longer logs spurious errors when browsing localhost, IP addresses, or other internal hosts; in those cases Waterfox now silently falls back to the global setting.
  • You can now disable cookie banner handling in Settings → Security & Privacy → Cookie Banner Blocker
  • Security fixes in MFSA-2025-94

Region & Geo Detection

What was happening

Firefox’s Region subsystem could still make a one‑time request to Mozilla’s privacy‑preserving geo‑IP service to infer your country on first run. That inferred “home region” is used by multiple subsystems (search, DoH rollout, feature gating, telemetry). The backend is designed to be privacy‑sensitive and only runs once, but it was still an unnecessary external connection we’d rather avoid.

What we’ve changed

  • Disabled network‑based region lookup
    • The URL used for region detection (browser.region.network.url) is now empty and locked.
    • Wi‑Fi–based region hints (browser.region.network.scan) was already disabled but is now locked as well.
  • Fixed, non‑dynamic “home region”
    • browser.search.region is now set to a fixed value (US) and locked.
    • This prevents any background attempts to “correct” or update your region based on IP.

Why this matters

No calls are made to Mozilla’s region/geo‑IP services for normal browsing and features that still look at region see a stable, non‑changing value instead of one inferred from your network.

AI & Machine Learning

What was happening

None of the Firefox AI features or settings (AI link previews, chat integrations, etc.) were enabled in Waterfox, and no AI processing was happening in the background. However, some of the underlying onboarding and Labs migration code for AI link previews would still run and surface onboarding pop‑ups or UI.

The underlying local ML runtime (used for various experimental features in upstream Firefox) was still present and technically enabled at the pref level, even though nothing was using it. Built‑in chatbot integration points were already off in Waterfox, but we’ve clarified and hardened the settings.

What we’ve changed

  • Core ML engine explicitly disabled

    • The main ML engine toggle browser.ml.enable now defaults to false.
    • Any feature that tries to create a local ML engine will now cleanly fail up front instead of starting an inference process.

  • AI link previews fully shut off

    • browser.ml.linkPreview.enabled is now false by default (and locked).
    • Legacy Firefox Labs state for link previews (browser.ml.linkPreview.labs) is forced to “not enrolled” and locked.
    • The opt‑in flag for AI key points (browser.ml.linkPreview.optin) is locked to false.
    • This prevents:
      • The feature from ever turning itself back on due to leftover Labs state.
      • Onboarding cards or AI link preview pop‑ups from appearing unexpectedly.

  • Chat sidebar integrations remain disabled

    • browser.ml.chat.enabled stays false, keeping built‑in chatbot UI off by default.

Why this matters

Local ML/AI code paths are no longer reachable unless you deliberately override multiple locked prefs. Users migrating profiles from Firefox (including Labs experiments) won’t see old experimental AI features unexpectedly re‑appear in Waterfox.

Experiments, Studies & “Labs”

What was happening

Waterfox already disabled Mozilla’s remote experimentation system (Normandy/Nimbus), but some features ran separately from this system (link previews).

What we’ve changed

  • For link previews specifically, we now:
    • Lock Labs and opt‑in prefs as described above.

Why this matters

Tours/onboarding for disabled features makes no sense and appears confusing.

Tip

Translations remain available

  • Full‑page and selection translations continue to work as before.
  • These use a separate engine and are not affected by disabling the generic ML runtime.

If you notice anything that still looks like geo detection, experimentation, or AI features sneaking in where they shouldn’t, please keep telling us as it helps us correct course faster!