diff --git a/README.md b/README.md
index f517187..2d193c4 100644
--- a/README.md
+++ b/README.md
@@ -359,7 +359,7 @@ Camoufox is a Firefox fork engineered for web scraping and AI agents. It is head
 * **Optimized for automation**
   * Human-like mouse movement 🖱️
   * Blocks & circumvents ads 🛡️
-  * No CSS animations 💨
+  * Optional instant animations (`instantAnimations`), so Playwright never waits on one 💨
 
 - Debloated & optimized for memory efficiency ⚡
 - [PyPI package](https://pypi.org/project/camoufox/) for updates & auto fingerprint injection 📦
@@ -427,7 +427,6 @@ Below is a list of patches and features implemented in Camoufox.
 - Network headers (Accept-Languages and User-Agent) are spoofed to match the navigator properties
 - WebRTC IP spoofing at the protocol level
 - Geolocation, timezone, and locale spoofing
-- Battery API spoofing
 - etc.
 
 ### Stealth patches
@@ -460,7 +459,7 @@ Below is a list of patches and features implemented in Camoufox.
 - Patches from LibreWolf & Ghostery to help remove telemetry & bloat
 - Debloat config from PeskyFox, LibreWolf, and others
 - Speed & network optimizations from FastFox
-- Removed all CSS animations
+- Animations run on stock timing; `instantAnimations: True` finishes them at once, at the cost of being detectable
 - Minimalistic theming
 - etc.
 
diff --git a/additions/camoucfg/MaskConfig.hpp b/additions/camoucfg/MaskConfig.hpp
index 813323f..efc90f9 100644
--- a/additions/camoucfg/MaskConfig.hpp
+++ b/additions/camoucfg/MaskConfig.hpp
@@ -212,18 +212,6 @@ inline std::optional<std::array<uint32_t, 4>> GetRect(
   return result;
 }
 
-inline std::optional<std::array<int32_t, 4>> GetInt32Rect(
-    const std::string& left, const std::string& top, const std::string& width,
-    const std::string& height) {
-  if (auto optValue = GetRect(left, top, width, height)) {
-    std::array<int32_t, 4> result;
-    std::transform(optValue->begin(), optValue->end(), result.begin(),
-                   [](const auto& val) { return static_cast<int32_t>(val); });
-    return result;
-  }
-  return std::nullopt;
-}
-
 // Helpers for WebGL
 
 inline std::optional<nlohmann::json> GetNested(const std::string& domain,
diff --git a/ci/tribal-rules.yml b/ci/tribal-rules.yml
index ed8f85f..73cc5b1 100644
--- a/ci/tribal-rules.yml
+++ b/ci/tribal-rules.yml
@@ -159,6 +159,32 @@ rules:
   # Measurement
   # -------------------------------------------------------------------------
 
+  - id: animations-run-on-stock-timing
+    title: Animations run on stock timing unless the caller opts into instantAnimations
+    check: automated
+    evidence:
+      - "measured on v152.0.4-beta.31: el.animate(frames, 1000).effect.getComputedTiming().duration returned 0, a 500ms transition 0"
+      - "the finished promise still resolved after ~1000ms, so the only saving was Playwright's stability wait"
+    rationale: >-
+      Instant animations were the default so Playwright never waited on one,
+      but any page reads the zero duration back in one line. Reporting the
+      real duration while not rendering the animation does not hide it
+      either: getComputedStyle or getBoundingClientRect sampled mid-animation
+      returns the end state. So the saving costs stealth, and it is the
+      caller's choice: `instantAnimations: True` turns it on and warns.
+
+  - id: spoofed-voices-speak
+    title: speak() on a spoofed voice starts, then ends after the text's duration
+    check: automated
+    evidence:
+      - "measured on v152.0.4-beta.31: speak() on a spoofed voice fired `error` after 3ms"
+      - "voices:fakeCompletion, the opt-out, fired start and end in the same tick"
+    rationale: >-
+      A spoofed voice has no engine behind it, and a real voice never errors
+      on a plain utterance or ends the instant it starts. So the browser
+      speaks it silently for as long as the text takes at ~150 words per
+      minute. The two config keys that chose between the two tells are gone.
+
   - id: no-glyph-spacing-noise
     title: Text is shaped exactly as stock Firefox shapes it; there is no spacing seed
     check: automated
diff --git a/native-tests/test_tribal_rules.py b/native-tests/test_tribal_rules.py
index 3a0a57a..2d216a7 100644
--- a/native-tests/test_tribal_rules.py
+++ b/native-tests/test_tribal_rules.py
@@ -542,6 +542,19 @@ def test_a_sandbox_held_over_a_page_window_is_nuked_not_just_dropped():
     )
 
 
+def test_instant_animations_are_an_opt_in():
+    patch = (REPO_ROOT / "patches" / "no-css-animations.patch").read_text(encoding="utf-8")
+    assert 'MaskConfig::GetBool("instantAnimations")' in patch, explain("animations-run-on-stock-timing")
+    assert "disableInstantAnimations" not in patch, explain("animations-run-on-stock-timing")
+
+
+def test_spoofed_voices_complete_without_a_config_switch():
+    patch = (REPO_ROOT / "patches" / "voice-spoofing.patch").read_text(encoding="utf-8")
+    assert "fakeCompletion" not in patch and "DispatchError(0, 0)" not in patch, (
+        explain("spoofed-voices-speak")
+    )
+
+
 def test_no_glyph_spacing_seed_anywhere():
     """No config key, no setter, no shaper hook."""
     declared = {
diff --git a/patches/browser-init.patch b/patches/browser-init.patch
index 63ef3a8..38699d3 100644
--- a/patches/browser-init.patch
+++ b/patches/browser-init.patch
@@ -1,10 +1,10 @@
 diff --git a/browser/base/content/browser-init.js b/browser/base/content/browser-init.js
-index 1cfa4b8497..bdf8d7202e 100644
+index 0aa4baea8e..3c964b7ad5 100644
 --- a/browser/base/content/browser-init.js
 +++ b/browser/base/content/browser-init.js
-@@ -3,6 +3,16 @@
-  * License, v. 2.0. If a copy of the MPL was not distributed with this
-  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+@@ -44,6 +44,16 @@ var gSerialDeviceObserver = {
+   },
+ };
  
 +const { AddonManager } = ChromeUtils.importESModule(
 +  "resource://gre/modules/AddonManager.sys.mjs",
@@ -19,7 +19,7 @@ index 1cfa4b8497..bdf8d7202e 100644
  let _resolveDelayedStartup;
  var delayedStartupPromise = new Promise(resolve => {
    _resolveDelayedStartup = resolve;
-@@ -72,7 +82,7 @@ var gBrowserInit = {
+@@ -157,7 +167,7 @@ var gBrowserInit = {
      updateBookmarkToolbarVisibility();
  
      // Set a sane starting width/height for all resolutions on new profiles.
@@ -28,7 +28,7 @@ index 1cfa4b8497..bdf8d7202e 100644
        // When the fingerprinting resistance is enabled, making sure that we don't
        // have a maximum window to interfere with generating rounded window dimensions.
        document.documentElement.setAttribute("sizemode", "normal");
-@@ -310,6 +320,22 @@ var gBrowserInit = {
+@@ -385,6 +395,22 @@ var gBrowserInit = {
      // Update UI if browser is under remote control.
      gRemoteControl.updateVisualCue();
  
@@ -51,7 +51,7 @@ index 1cfa4b8497..bdf8d7202e 100644
      // If we are given a tab to swap in, take care of it before first paint to
      // avoid an about:blank flash.
      let tabToAdopt = this.getTabToAdopt();
-@@ -345,6 +371,33 @@ var gBrowserInit = {
+@@ -448,6 +474,33 @@ var gBrowserInit = {
        }
      }
  
@@ -85,8 +85,8 @@ index 1cfa4b8497..bdf8d7202e 100644
      // Wait until chrome is painted before executing code not critical to making the window visible
      this._boundDelayedStartup = this._delayedStartup.bind(this);
      window.addEventListener("MozAfterPaint", this._boundDelayedStartup);
-@@ -366,9 +417,177 @@ var gBrowserInit = {
-       )?.removeAttribute("key");
+@@ -475,9 +528,177 @@ var gBrowserInit = {
+       }
      }
  
 +    // Set default size
@@ -132,8 +132,8 @@ index 1cfa4b8497..bdf8d7202e 100644
 +    browser.style.setProperty('box-sizing', 'content-box');
 +
 +    // Hijack the inner window size
-+    let innerWidth = ChromeUtils.camouGetInt("window.innerWidth") || ChromeUtils.camouGetInt("document.body.clientWidth");
-+    let innerHeight = ChromeUtils.camouGetInt("window.innerHeight") || ChromeUtils.camouGetInt("document.body.clientHeight");
++    let innerWidth = ChromeUtils.camouGetInt("window.innerWidth");
++    let innerHeight = ChromeUtils.camouGetInt("window.innerHeight");
 +
 +    if (innerWidth || innerHeight) {
 +      let win_inner_style = document.createElement('style');
diff --git a/patches/fingerprint-injection.patch b/patches/fingerprint-injection.patch
index 406a70d..a4cdcc7 100644
--- a/patches/fingerprint-injection.patch
+++ b/patches/fingerprint-injection.patch
@@ -1,8 +1,8 @@
 diff --git a/browser/app/moz.build b/browser/app/moz.build
-index a23bb7812a..58942ccb13 100644
+index 28a9650680..9251ac4547 100644
 --- a/browser/app/moz.build
 +++ b/browser/app/moz.build
-@@ -182,6 +182,9 @@ for icon in ("firefox", "document", "newwindow", "newtab", "pbmode", "document_p
+@@ -186,6 +186,9 @@ for icon in ("firefox", "document", "newwindow", "newtab", "pbmode", "document_p
          icon,
      )
  
@@ -12,43 +12,11 @@ index a23bb7812a..58942ccb13 100644
  if CONFIG["MOZ_ASAN"] or CONFIG["MOZ_DEBUG"]:
      WINCONSOLE = True
  else:
-diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
-index 101590d8c8..f004930b20 100644
---- a/dom/base/Element.cpp
-+++ b/dom/base/Element.cpp
-@@ -12,6 +12,8 @@
- 
- #include "mozilla/dom/Element.h"
- 
-+#include "MaskConfig.hpp"
-+
- #include <inttypes.h>
- 
- #include <cstddef>
-@@ -1006,6 +1008,18 @@ nsRect Element::GetClientAreaRect() {
-   Document* doc = OwnerDoc();
-   nsPresContext* presContext = doc->GetPresContext();
- 
-+  if (doc->GetBodyElement() == this) {
-+    if (auto conf = MaskConfig::GetInt32Rect(
-+            "document.body.clientLeft", "document.body.clientTop",
-+            "document.body.clientWidth", "document.body.clientHeight")) {
-+      if (conf.has_value()) {
-+        auto values = conf.value();
-+        return nsRect(values[0] * 60, values[1] * 60, values[2] * 60,
-+                      values[3] * 60);
-+      }
-+    }
-+  }
-+
-   // We can avoid a layout flush if this is the scrolling element of the
-   // document, we have overlay scrollbars, and we aren't embedded in another
-   // document
 diff --git a/dom/base/moz.build b/dom/base/moz.build
-index cd9090cda3..37a053579e 100644
+index e25ac44451..13839534ad 100644
 --- a/dom/base/moz.build
 +++ b/dom/base/moz.build
-@@ -634,3 +634,6 @@ GeneratedFile(
+@@ -647,3 +647,6 @@ GeneratedFile(
          "/servo/components/style/properties/counted_unknown_properties.py",
      ],
  )
@@ -57,10 +25,10 @@ index cd9090cda3..37a053579e 100644
 +LOCAL_INCLUDES += ["/camoucfg"]
 \ No newline at end of file
 diff --git a/dom/base/nsGlobalWindowInner.cpp b/dom/base/nsGlobalWindowInner.cpp
-index 330a707789..241f87780b 100644
+index 4bc6688f9a..693779ca08 100644
 --- a/dom/base/nsGlobalWindowInner.cpp
 +++ b/dom/base/nsGlobalWindowInner.cpp
-@@ -5,6 +5,7 @@
+@@ -3,6 +3,7 @@
   * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  
  #include "nsGlobalWindowInner.h"
@@ -68,7 +36,7 @@ index 330a707789..241f87780b 100644
  
  #include <inttypes.h>
  #include <stdio.h>
-@@ -3439,6 +3440,8 @@ void nsGlobalWindowInner::SetName(const nsAString& aName,
+@@ -3704,6 +3705,8 @@ void nsGlobalWindowInner::SetName(const nsAString& aName,
  }
  
  double nsGlobalWindowInner::GetInnerWidth(ErrorResult& aError) {
@@ -77,7 +45,7 @@ index 330a707789..241f87780b 100644
    FORWARD_TO_OUTER_OR_THROW(GetInnerWidthOuter, (aError), aError, 0);
  }
  
-@@ -3450,6 +3453,8 @@ nsresult nsGlobalWindowInner::GetInnerWidth(double* aWidth) {
+@@ -3715,6 +3718,8 @@ nsresult nsGlobalWindowInner::GetInnerWidth(double* aWidth) {
  }
  
  double nsGlobalWindowInner::GetInnerHeight(ErrorResult& aError) {
@@ -86,7 +54,7 @@ index 330a707789..241f87780b 100644
    // We ignore aCallerType; we only have that argument because some other things
    // called by GetReplaceableWindowCoord need it.  If this ever changes, fix
    //   nsresult nsGlobalWindowInner::GetInnerHeight(double* aInnerWidth)
-@@ -3466,12 +3471,18 @@ nsresult nsGlobalWindowInner::GetInnerHeight(double* aHeight) {
+@@ -3731,6 +3736,12 @@ nsresult nsGlobalWindowInner::GetInnerHeight(double* aHeight) {
  
  int32_t nsGlobalWindowInner::GetOuterWidth(CallerType aCallerType,
                                             ErrorResult& aError) {
@@ -99,13 +67,7 @@ index 330a707789..241f87780b 100644
    FORWARD_TO_OUTER_OR_THROW(GetOuterWidthOuter, (aCallerType, aError), aError,
                              0);
  }
- 
- int32_t nsGlobalWindowInner::GetOuterHeight(CallerType aCallerType,
-                                             ErrorResult& aError) {
-   FORWARD_TO_OUTER_OR_THROW(GetOuterHeightOuter, (aCallerType, aError), aError,
-                             0);
- }
-@@ -3486,11 +3497,13 @@ double nsGlobalWindowInner::ScreenEdgeSlopY() const {
+@@ -3751,11 +3762,13 @@ double nsGlobalWindowInner::ScreenEdgeSlopY() const {
  
  int32_t nsGlobalWindowInner::GetScreenX(CallerType aCallerType,
                                          ErrorResult& aError) {
@@ -119,7 +81,7 @@ index 330a707789..241f87780b 100644
    FORWARD_TO_OUTER_OR_THROW(GetScreenYOuter, (aCallerType, aError), aError, 0);
  }
  
-@@ -3524,6 +3537,8 @@ static nsPresContext* GetPresContextForRatio(Document* aDoc) {
+@@ -3789,6 +3802,8 @@ static nsPresContext* GetPresContextForRatio(Document* aDoc) {
  double nsGlobalWindowInner::GetDevicePixelRatio(CallerType aCallerType,
                                                  ErrorResult& aError) {
    ENSURE_ACTIVE_DOCUMENT(aError, 0.0);
@@ -128,80 +90,20 @@ index 330a707789..241f87780b 100644
  
    RefPtr<nsPresContext> presContext = GetPresContextForRatio(mDoc);
    if (NS_WARN_IF(!presContext)) {
-@@ -3594,26 +3609,38 @@ already_AddRefed<MediaQueryList> nsGlobalWindowInner::MatchMedia(
- }
- 
- int32_t nsGlobalWindowInner::GetScrollMinX(ErrorResult& aError) {
-+  if (auto value = MaskConfig::GetInt32("window.scrollMinX"))
-+    return value.value();
-   FORWARD_TO_OUTER_OR_THROW(GetScrollBoundaryOuter, (eSideLeft), aError, 0);
- }
- 
- int32_t nsGlobalWindowInner::GetScrollMinY(ErrorResult& aError) {
-+  if (auto value = MaskConfig::GetInt32("window.scrollMinY"))
-+    return value.value();
-   FORWARD_TO_OUTER_OR_THROW(GetScrollBoundaryOuter, (eSideTop), aError, 0);
- }
- 
- int32_t nsGlobalWindowInner::GetScrollMaxX(ErrorResult& aError) {
-+  if (auto value = MaskConfig::GetInt32("window.scrollMaxX"))
-+    return value.value();
-   FORWARD_TO_OUTER_OR_THROW(GetScrollBoundaryOuter, (eSideRight), aError, 0);
- }
- 
- int32_t nsGlobalWindowInner::GetScrollMaxY(ErrorResult& aError) {
-+  if (auto value = MaskConfig::GetInt32("window.scrollMaxY"))
-+    return value.value();
-   FORWARD_TO_OUTER_OR_THROW(GetScrollBoundaryOuter, (eSideBottom), aError, 0);
- }
- 
- double nsGlobalWindowInner::GetScrollX(ErrorResult& aError) {
-+  if (auto value = MaskConfig::GetDouble("screen.pageXOffset"))
-+    return value.value();
-   FORWARD_TO_OUTER_OR_THROW(GetScrollXOuter, (), aError, 0);
- }
- 
- double nsGlobalWindowInner::GetScrollY(ErrorResult& aError) {
-+  if (auto value = MaskConfig::GetDouble("screen.pageYOffset"))
-+    return value.value();
-   FORWARD_TO_OUTER_OR_THROW(GetScrollYOuter, (), aError, 0);
- }
- 
-diff --git a/dom/base/nsHistory.cpp b/dom/base/nsHistory.cpp
-index e2fd8e6389..e5ddf4e08c 100644
---- a/dom/base/nsHistory.cpp
-+++ b/dom/base/nsHistory.cpp
-@@ -5,6 +5,7 @@
-  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
- 
- #include "nsHistory.h"
-+#include "MaskConfig.hpp"
- 
- #include "jsapi.h"
- #include "mozilla/RefPtr.h"
-@@ -64,6 +65,8 @@ JSObject* nsHistory::WrapObject(JSContext* aCx,
- }
- 
- uint32_t nsHistory::GetLength(ErrorResult& aRv) const {
-+  if (auto value = MaskConfig::GetUint32("window.history.length"))
-+    return value.value();
-   nsCOMPtr<nsPIDOMWindowInner> win(do_QueryReferent(mInnerWindow));
-   if (!win || !win->HasActiveDocument()) {
-     aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
 diff --git a/dom/base/nsScreen.cpp b/dom/base/nsScreen.cpp
-index 306ab35772..7f7728a6cc 100644
+index de9a6a4d11..78849001c5 100644
 --- a/dom/base/nsScreen.cpp
 +++ b/dom/base/nsScreen.cpp
-@@ -6,6 +6,8 @@
+@@ -4,6 +4,8 @@
  
  #include "nsScreen.h"
  
 +#include "MaskConfig.hpp"
 +
  #include "mozilla/GeckoBindings.h"
+ #include "mozilla/dom/BrowsingContextBinding.h"
  #include "mozilla/dom/Document.h"
- #include "mozilla/dom/DocumentInlines.h"
-@@ -40,6 +42,10 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(nsScreen, DOMEventTargetHelper,
+@@ -44,6 +46,10 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(nsScreen, DOMEventTargetHelper,
                                     mScreenOrientation)
  
  int32_t nsScreen::PixelDepth() {
@@ -212,7 +114,7 @@ index 306ab35772..7f7728a6cc 100644
    // Return 24 to prevent fingerprinting.
    if (ShouldResistFingerprinting(RFPTarget::ScreenPixelDepth)) {
      return 24;
-@@ -89,6 +95,12 @@ CSSIntRect nsScreen::GetRect() {
+@@ -99,6 +105,12 @@ CSSIntRect nsScreen::GetRect() {
  }
  
  CSSIntRect nsScreen::GetAvailRect() {
@@ -225,79 +127,19 @@ index 306ab35772..7f7728a6cc 100644
    // Return window inner rect to prevent fingerprinting.
    if (ShouldResistFingerprinting(RFPTarget::ScreenAvailRect)) {
      return GetTopWindowInnerRectForRFP();
-diff --git a/dom/battery/BatteryManager.cpp b/dom/battery/BatteryManager.cpp
-index 6322093fd9..264cc91bd1 100644
---- a/dom/battery/BatteryManager.cpp
-+++ b/dom/battery/BatteryManager.cpp
-@@ -9,6 +9,7 @@
- #include <cmath>
- #include <limits>
- 
-+#include "MaskConfig.hpp"
- #include "Constants.h"
- #include "mozilla/DOMEventTargetHelper.h"
- #include "mozilla/Hal.h"
-@@ -53,6 +54,9 @@ JSObject* BatteryManager::WrapObject(JSContext* aCx,
- 
- bool BatteryManager::Charging() const {
-   MOZ_ASSERT(NS_IsMainThread());
-+  if (auto value = MaskConfig::GetBool("battery:charging"); value.has_value())
-+    return value.value();
-+
-   // For testing, unable to report the battery status information
-   if (Preferences::GetBool("dom.battery.test.default", false)) {
-     return true;
-@@ -69,6 +73,8 @@ bool BatteryManager::Charging() const {
- 
- double BatteryManager::DischargingTime() const {
-   MOZ_ASSERT(NS_IsMainThread());
-+  if (auto value = MaskConfig::GetDouble("battery:dischargingTime"))
-+    return value.value();
-   // For testing, unable to report the battery status information
-   if (Preferences::GetBool("dom.battery.test.default", false)) {
-     return std::numeric_limits<double>::infinity();
-@@ -86,6 +92,8 @@ double BatteryManager::DischargingTime() const {
- 
- double BatteryManager::ChargingTime() const {
-   MOZ_ASSERT(NS_IsMainThread());
-+  if (auto value = MaskConfig::GetDouble("battery:chargingTime"))
-+    return value.value();
-   // For testing, unable to report the battery status information
-   if (Preferences::GetBool("dom.battery.test.default", false)) {
-     return 0.0;
-@@ -103,6 +111,7 @@ double BatteryManager::ChargingTime() const {
- 
- double BatteryManager::Level() const {
-   MOZ_ASSERT(NS_IsMainThread());
-+  if (auto value = MaskConfig::GetDouble("battery:level")) return value.value();
-   // For testing, unable to report the battery status information
-   if (Preferences::GetBool("dom.battery.test.default")) {
-     return 1.0;
-diff --git a/dom/battery/moz.build b/dom/battery/moz.build
-index 3a90c93c01..91d673039b 100644
---- a/dom/battery/moz.build
-+++ b/dom/battery/moz.build
-@@ -21,3 +21,6 @@ FINAL_LIBRARY = "xul"
- 
- MOCHITEST_CHROME_MANIFESTS += ["test/chrome.toml"]
- MOCHITEST_MANIFESTS += ["test/mochitest.toml"]
-+
-+# DOM Mask
-+LOCAL_INCLUDES += ["/camoucfg"]
-\ No newline at end of file
 diff --git a/dom/workers/WorkerNavigator.cpp b/dom/workers/WorkerNavigator.cpp
-index 622724b529..c9a65ff013 100644
+index e9ebd3e01b..c6f64371f2 100644
 --- a/dom/workers/WorkerNavigator.cpp
 +++ b/dom/workers/WorkerNavigator.cpp
-@@ -5,6 +5,7 @@
+@@ -3,6 +3,7 @@
   * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  
  #include "mozilla/dom/WorkerNavigator.h"
 +#include "MaskConfig.hpp"
  
- #include <utility>
- 
-@@ -103,6 +104,9 @@ JSObject* WorkerNavigator::WrapObject(JSContext* aCx,
+ #include "ErrorList.h"
+ #include "MainThreadUtils.h"
+@@ -106,6 +107,9 @@ JSObject* WorkerNavigator::WrapObject(JSContext* aCx,
  }
  
  bool WorkerNavigator::GlobalPrivacyControl() const {
@@ -307,7 +149,7 @@ index 622724b529..c9a65ff013 100644
    bool gpcStatus = StaticPrefs::privacy_globalprivacycontrol_enabled();
    if (!gpcStatus) {
      JSObject* jso = GetWrapper();
-@@ -125,6 +129,8 @@ void WorkerNavigator::SetLanguages(const nsTArray<nsString>& aLanguages) {
+@@ -128,6 +132,8 @@ void WorkerNavigator::SetLanguages(const nsTArray<nsString>& aLanguages) {
  void WorkerNavigator::GetAppVersion(nsString& aAppVersion,
                                      CallerType aCallerType,
                                      ErrorResult& aRv) const {
@@ -316,7 +158,7 @@ index 622724b529..c9a65ff013 100644
    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
    MOZ_ASSERT(workerPrivate);
  
-@@ -147,6 +153,8 @@ void WorkerNavigator::GetAppVersion(nsString& aAppVersion,
+@@ -150,6 +156,8 @@ void WorkerNavigator::GetAppVersion(nsString& aAppVersion,
  
  void WorkerNavigator::GetPlatform(nsString& aPlatform, CallerType aCallerType,
                                    ErrorResult& aRv) const {
@@ -325,7 +167,7 @@ index 622724b529..c9a65ff013 100644
    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
    MOZ_ASSERT(workerPrivate);
  
-@@ -207,6 +215,8 @@ class GetUserAgentRunnable final : public WorkerMainThreadRunnable {
+@@ -210,6 +218,8 @@ class GetUserAgentRunnable final : public WorkerMainThreadRunnable {
  
  void WorkerNavigator::GetUserAgent(nsString& aUserAgent, CallerType aCallerType,
                                     ErrorResult& aRv) const {
@@ -334,7 +176,7 @@ index 622724b529..c9a65ff013 100644
    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
    MOZ_ASSERT(workerPrivate);
  
-@@ -218,6 +228,8 @@ void WorkerNavigator::GetUserAgent(nsString& aUserAgent, CallerType aCallerType,
+@@ -221,6 +231,8 @@ void WorkerNavigator::GetUserAgent(nsString& aUserAgent, CallerType aCallerType,
  }
  
  uint64_t WorkerNavigator::HardwareConcurrency() const {
@@ -344,10 +186,10 @@ index 622724b529..c9a65ff013 100644
    MOZ_ASSERT(rts);
  
 diff --git a/dom/workers/moz.build b/dom/workers/moz.build
-index 2f2948a729..b8ad10403f 100644
+index f5ec1301a7..294a1c7a03 100644
 --- a/dom/workers/moz.build
 +++ b/dom/workers/moz.build
-@@ -114,3 +114,6 @@ MARIONETTE_MANIFESTS += ["test/marionette/manifest.toml"]
+@@ -110,3 +110,6 @@ MARIONETTE_MANIFESTS += ["test/marionette/manifest.toml"]
  XPCSHELL_TESTS_MANIFESTS += ["test/xpcshell/xpcshell.toml"]
  
  BROWSER_CHROME_MANIFESTS += ["test/browser.toml"]
diff --git a/patches/no-css-animations.patch b/patches/no-css-animations.patch
index c9dfb31..8d8848d 100644
--- a/patches/no-css-animations.patch
+++ b/patches/no-css-animations.patch
@@ -1,5 +1,5 @@
 diff --git a/dom/animation/AnimationEffect.cpp b/dom/animation/AnimationEffect.cpp
-index e92fdc9268..5f3fa86940 100644
+index e92fdc9268..9c04f00200 100644
 --- a/dom/animation/AnimationEffect.cpp
 +++ b/dom/animation/AnimationEffect.cpp
 @@ -11,6 +11,7 @@
@@ -10,7 +10,7 @@ index e92fdc9268..5f3fa86940 100644
  
  namespace mozilla::dom {
  
-@@ -121,10 +122,19 @@ ComputedTiming AnimationEffect::GetComputedTimingAt(
+@@ -121,10 +122,20 @@ ComputedTiming AnimationEffect::GetComputedTimingAt(
    // Always return the same object to benefit from return-value optimization.
    ComputedTiming result;
  
@@ -19,19 +19,20 @@ index e92fdc9268..5f3fa86940 100644
      MOZ_ASSERT(aTiming.Duration().ref() >= zeroDuration,
                 "Iteration duration should be positive");
 -    result.mDuration = aTiming.Duration().ref();
-+    // Camoufox: finite CSS animations complete instantly so Playwright doesn't
-+    // wait on them. `disableInstantAnimations` restores normal animation timing.
-+    if (MaskConfig::GetBool("disableInstantAnimations") ||
-+        result.mActiveDuration == StickyTimeDuration::Forever()) {
-+      result.mDuration = aTiming.Duration().ref();
-+    } else {
++    // Camoufox: `instantAnimations` completes finite animations at once so
++    // Playwright never waits on them. Off by default: a page reads the zero
++    // duration back through getComputedTiming().
++    if (MaskConfig::GetBool("instantAnimations") &&
++        result.mActiveDuration != StickyTimeDuration::Forever()) {
 +      result.mDuration = zeroDuration;
 +      result.mActiveDuration = zeroDuration;
++    } else {
++      result.mDuration = aTiming.Duration().ref();
 +    }
    }
  
    MOZ_ASSERT(aTiming.Iterations() >= 0.0 && !std::isnan(aTiming.Iterations()),
-@@ -137,7 +147,6 @@ ComputedTiming AnimationEffect::GetComputedTimingAt(
+@@ -137,7 +148,6 @@ ComputedTiming AnimationEffect::GetComputedTimingAt(
               "ValidateIterationStart");
    result.mIterationStart = aTiming.IterationStart();
  
diff --git a/patches/patch-dependencies.md b/patches/patch-dependencies.md
index cd2570f..1aa0d55 100644
--- a/patches/patch-dependencies.md
+++ b/patches/patch-dependencies.md
@@ -25,7 +25,7 @@ be listed there.
 | `audio-context-spoofing.patch` | `AudioContext:outputLatency` |
 | `audio-fingerprint-manager.patch` | `audio:seed` |
 | `chromeutil.patch` | `debug` |
-| `fingerprint-injection.patch` | `navigator.*`, `screen.*`, `window.*`, `battery:*` |
+| `fingerprint-injection.patch` | `navigator.*`, `screen.*`, `window.*` |
 | `font-hijacker.patch` | `navigator.platform` |
 | `font-system-fonts-css2.patch` | `navigator.platform`, `window.devicePixelRatio` |
 | `force-default-pointer.patch` | `navigator.maxTouchPoints` |
@@ -36,7 +36,7 @@ be listed there.
 | `media-device-spoofing.patch` | `mediaDevices:*` |
 | `navigator-spoofing.patch` | `navigator.*`, `timezone` |
 | `network-patches.patch` | `headers.*`, `navigator.userAgent` |
-| `no-css-animations.patch` | `disableInstantAnimations` |
+| `no-css-animations.patch` | `instantAnimations` |
 | `screen-spoofing.patch` | `screen.width`, `screen.height` |
 | `system-ui-font-spoofing.patch` | `navigator.platform` |
 | `timezone-spoofing.patch` | `timezone` |
diff --git a/patches/voice-spoofing.patch b/patches/voice-spoofing.patch
index 4d4a268..170ba19 100644
--- a/patches/voice-spoofing.patch
+++ b/patches/voice-spoofing.patch
@@ -1,27 +1,29 @@
 diff --git a/dom/media/webspeech/synth/moz.build b/dom/media/webspeech/synth/moz.build
+index ca6ffacb21..fb661fd69e 100644
 --- a/dom/media/webspeech/synth/moz.build
 +++ b/dom/media/webspeech/synth/moz.build
-@@ -63,2 +63,5 @@
+@@ -62,3 +62,6 @@ LOCAL_INCLUDES += [
+     "/dom/base",
      "ipc",
  ]
 +
 +# DOM Mask
 +LOCAL_INCLUDES += ['/camoucfg']
-
 diff --git a/dom/media/webspeech/synth/nsSynthVoiceRegistry.cpp b/dom/media/webspeech/synth/nsSynthVoiceRegistry.cpp
-index e5a1353d6b..4a4a5b080b 100644
+index 3648239545..48e195a684 100644
 --- a/dom/media/webspeech/synth/nsSynthVoiceRegistry.cpp
 +++ b/dom/media/webspeech/synth/nsSynthVoiceRegistry.cpp
-@@ -26,7 +26,8 @@
+@@ -23,7 +23,9 @@
+ #include "nsServiceManagerUtils.h"
  #include "nsSpeechTask.h"
  #include "nsString.h"
++#include "nsThreadUtils.h"
  
 +#include "MaskConfig.hpp"
  using mozilla::intl::LocaleService;
  
- namespace mozilla::dom {
- 
-@@ -169,6 +171,20 @@
+ #undef LOG
+@@ -165,6 +167,20 @@ nsSynthVoiceRegistry* nsSynthVoiceRegistry::GetInstance() {
        // Start up all speech synth services.
        NS_CreateServicesFromCategory(NS_SPEECH_SYNTH_STARTED, nullptr,
                                      NS_SPEECH_SYNTH_STARTED);
@@ -42,7 +44,7 @@ index e5a1353d6b..4a4a5b080b 100644
      }
    }
  
-@@ -305,6 +320,21 @@ nsSynthVoiceRegistry::AddVoice(nsISpeechService* aService,
+@@ -301,6 +317,21 @@ nsSynthVoiceRegistry::AddVoice(nsISpeechService* aService,
      return NS_ERROR_NOT_AVAILABLE;
    }
  
@@ -64,7 +66,7 @@ index e5a1353d6b..4a4a5b080b 100644
    return AddVoiceImpl(aService, aUri, aName, aLang, aLocalService,
                        aQueuesUtterances);
  }
-@@ -779,6 +796,35 @@ void nsSynthVoiceRegistry::SpeakImpl(VoiceData* aVoice, nsSpeechTask* aTask,
+@@ -775,6 +806,30 @@ void nsSynthVoiceRegistry::SpeakImpl(VoiceData* aVoice, nsSpeechTask* aTask,
         NS_ConvertUTF16toUTF8(aText).get(),
         NS_ConvertUTF16toUTF8(aVoice->mUri).get(), aRate, aPitch));
  
@@ -72,26 +74,21 @@ index e5a1353d6b..4a4a5b080b 100644
 +  if (auto voices = MaskConfig::MVoices()) {
 +    for (const auto& [lang, name, uri, isDefault, isLocal] : voices.value()) {
 +      if (NS_ConvertUTF8toUTF16(uri).Equals(aVoice->mUri)) {
-+        printf_stderr("Tried to speak a fake voice: %s",
-+                      NS_ConvertUTF16toUTF8(aVoice->mUri).get());
++        // A spoofed voice has no engine behind it. Speak it silently for as
++        // long as the text takes at ~150 words per minute, so start and end
++        // arrive when they would from a real voice.
 +        aTask->Init();
-+        // If fake completion is disabled, throw an error
-+        if (!MaskConfig::GetBool("voices:fakeCompletion")) {
-+          aTask->DispatchError(0, 0);
-+          return;
-+        }
-+        float charsPerSecond;
-+        if (auto value =
-+                MaskConfig::GetDouble("voices:fakeCompletion:charsPerSecond")) {
-+          charsPerSecond = value.value();
-+        } else {
-+          charsPerSecond = 12.5f;
-+        }
-+        // Return a fake success with a speach rate of 150wpm
 +        aTask->DispatchStart();
-+        float fakeElapsedTime =
-+            static_cast<float>(aText.Length()) / (charsPerSecond * aRate);
-+        aTask->DispatchEnd(fakeElapsedTime, aText.Length());
++        const float elapsed =
++            static_cast<float>(aText.Length()) / (12.5f * aRate);
++        RefPtr<nsSpeechTask> task = aTask;
++        const uint32_t length = aText.Length();
++        NS_DelayedDispatchToCurrentThread(
++            NS_NewRunnableFunction("CamouFakeSpeechEnd",
++                                   [task, elapsed, length]() {
++                                     (void)task->DispatchEnd(elapsed, length);
++                                   }),
++            static_cast<uint32_t>(elapsed * 1000));
 +        return;
 +      }
 +    }
diff --git a/pythonlib/camoufox/fpgen.yml b/pythonlib/camoufox/fpgen.yml
index c3f5d33..eb31c69 100644
--- a/pythonlib/camoufox/fpgen.yml
+++ b/pythonlib/camoufox/fpgen.yml
@@ -59,7 +59,6 @@ window:
   # bottom edge land (see BROWSER_CHROME_HEIGHT in coherence.py).
   screenX: window.screenX
   screenY: window.screenY
-  pageYOffset: screen.pageYOffset
   # devicePixelRatio is not mapped: any value but 1 is a spoofing tell unless
   # the whole geometry is scaled with it.
 
diff --git a/pythonlib/camoufox/utils.py b/pythonlib/camoufox/utils.py
index ab77595..3b63857 100644
--- a/pythonlib/camoufox/utils.py
+++ b/pythonlib/camoufox/utils.py
@@ -575,6 +575,8 @@ def warn_manual_config(config: Dict[str, Any]) -> None:
     # CSS pointer media queries and the TouchEvent interfaces.
     if is_domain_set(config, 'navigator.maxTouchPoints'):
         LeakWarning.warn('max_touch_points', False)
+    if config.get('instantAnimations'):
+        LeakWarning.warn('instant_animations', False)
     # Manual screen/window setting
     if is_domain_set(config, 'screen.', 'window.', 'document.body.'):
         LeakWarning.warn('viewport', False)
@@ -585,8 +587,6 @@ _WINDOW_DIM_KEYS = (
     'window.outerHeight',
     'window.innerWidth',
     'window.innerHeight',
-    'document.body.clientWidth',
-    'document.body.clientHeight',
 )
 
 
diff --git a/pythonlib/camoufox/warnings.yml b/pythonlib/camoufox/warnings.yml
index 4db3968..2a51e9e 100644
--- a/pythonlib/camoufox/warnings.yml
+++ b/pythonlib/camoufox/warnings.yml
@@ -36,6 +36,11 @@ no_region: >-
     Because you did not pass in a locale region, Camoufox will generate one for you.
     This can cause suspicion if your IP does not match your locale region.
 
+instant_animations: >-
+    instantAnimations makes every finite animation finish at once, so Playwright
+    never waits on one. A page can see it: getComputedTiming() reports a duration
+    of 0 where stock Firefox reports the real one.
+
 block_webgl: >-
     Disabling WebGL is not recommended. Many WAFs will check if WebGL is enabled.
 
diff --git a/pythonlib/tests/test_identity_salt.py b/pythonlib/tests/test_identity_salt.py
index 50ffe26..24a7cdd 100644
--- a/pythonlib/tests/test_identity_salt.py
+++ b/pythonlib/tests/test_identity_salt.py
@@ -194,3 +194,10 @@ def test_config_overrides_reach_the_config_and_the_init_script():
     context = fp.generate_context_fingerprint(os="linux", config_overrides={"audio:seed": 7})
     assert context["config"]["audio:seed"] == 7
     assert "setAudioFingerprintSeed(7)" in context["init_script"]
+
+
+def test_instant_animations_warn_that_they_are_detectable():
+    from camoufox._warnings import LeakWarning
+
+    with pytest.warns(LeakWarning, match="getComputedTiming"):
+        launch(config={"instantAnimations": True}, i_know_what_im_doing=False)
diff --git a/pythonlib/tests/test_viewport_default.py b/pythonlib/tests/test_viewport_default.py
index 70e9eb5..a14757b 100644
--- a/pythonlib/tests/test_viewport_default.py
+++ b/pythonlib/tests/test_viewport_default.py
@@ -22,7 +22,6 @@ def _opts(config_blob: str):
     [
         ('{"window.outerWidth": 360}', True),
         ('{"window.innerHeight": 740}', True),
-        ('{"document.body.clientWidth": 360}', True),
         ('{"screen.width": 360}', False),
         ('{"navigator.userAgent": "x"}', False),
         ("{}", False),
diff --git a/settings/properties.json b/settings/properties.json
index 4aee6b6..078cdab 100644
--- a/settings/properties.json
+++ b/settings/properties.json
@@ -17,33 +17,18 @@
   { "property": "screen.width", "type": "uint" },
   { "property": "screen.colorDepth", "type": "uint" },
   { "property": "screen.pixelDepth", "type": "uint" },
-  { "property": "screen.pageXOffset", "type": "double" },
-  { "property": "screen.pageYOffset", "type": "double" },
-  { "property": "window.scrollMinX", "type": "int" },
-  { "property": "window.scrollMinY", "type": "int" },
-  { "property": "window.scrollMaxX", "type": "int" },
-  { "property": "window.scrollMaxY", "type": "int" },
   { "property": "window.outerHeight", "type": "uint" },
   { "property": "window.outerWidth", "type": "uint" },
   { "property": "window.innerHeight", "type": "uint" },
   { "property": "window.innerWidth", "type": "uint" },
   { "property": "window.screenX", "type": "int" },
   { "property": "window.screenY", "type": "int" },
-  { "property": "window.history.length", "type": "uint" },
   { "property": "window.devicePixelRatio", "type": "double" },
-  { "property": "document.body.clientWidth", "type": "uint" },
-  { "property": "document.body.clientHeight", "type": "uint" },
-  { "property": "document.body.clientTop", "type": "uint" },
-  { "property": "document.body.clientLeft", "type": "uint" },
   { "property": "headers.User-Agent", "type": "str" },
   { "property": "headers.Accept-Language", "type": "str" },
   { "property": "headers.Accept-Encoding", "type": "str" },
   { "property": "webrtc:ipv4", "type": "str" },
   { "property": "webrtc:ipv6", "type": "str" },
-  { "property": "battery:charging", "type": "bool" },
-  { "property": "battery:chargingTime", "type": "double" },
-  { "property": "battery:dischargingTime", "type": "double" },
-  { "property": "battery:level", "type": "double" },
   { "property": "fonts", "type": "array" },
   { "property": "audio:seed", "type": "uint" },
   { "property": "geolocation:latitude", "type": "double" },
@@ -75,8 +60,6 @@
   { "property": "webGl2:contextAttributes", "type": "dict" },
   { "property": "voices", "type": "array" },
   { "property": "voices:blockIfNotDefined", "type": "bool" },
-  { "property": "voices:fakeCompletion", "type": "bool" },
-  { "property": "voices:fakeCompletion:charsPerSecond", "type": "double" },
   { "property": "mediaDevices:micros", "type": "uint" },
   { "property": "mediaDevices:webcams", "type": "uint" },
   { "property": "mediaDevices:speakers", "type": "uint" },
@@ -94,7 +77,7 @@
   { "property": "forceScopeAccess", "type": "bool" },
 
   { "property": "disableTheming", "type": "bool" },
-  { "property": "disableInstantAnimations", "type": "bool" },
+  { "property": "instantAnimations", "type": "bool" },
   { "property": "addons", "type": "array" },
   { "property": "certificatePaths", "type": "array" },
   { "property": "certificates", "type": "array" },
diff --git a/tests/patches/animation-timing.py b/tests/patches/animation-timing.py
new file mode 100644
index 0000000..eff5b35
--- /dev/null
+++ b/tests/patches/animation-timing.py
@@ -0,0 +1,66 @@
+"""
+Verify animations run on stock timing unless `instantAnimations` is set.
+
+no-css-animations.patch can finish every finite animation at once, so Playwright
+never waits on one. That used to be the default, and a page could read it back in
+one line: `el.animate(frames, 1000).effect.getComputedTiming().duration` was 0
+where stock Firefox reports 1000, and a CSS transition reported 0 as well. It is
+now an opt-in.
+
+What PASS means:
+    * by default, a 1000ms Web Animation and a 500ms CSS transition report
+      their real durations;
+    * with config {"instantAnimations": True}, both report 0.
+
+    python tests/patches/animation-timing.py
+"""
+
+import asyncio
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+from helpers import resolve_binary  # noqa: E402
+
+PROBE = """() => {
+  const animation = document.body.animate([{opacity: 0}, {opacity: 1}], 1000);
+  const el = document.createElement('div');
+  document.body.append(el);
+  el.style.transition = 'opacity 500ms';
+  el.style.opacity = '0';
+  el.offsetWidth;
+  el.style.opacity = '1';
+  return {
+    animation: animation.effect.getComputedTiming().duration,
+    transition: el.getAnimations().map(a => a.effect.getComputedTiming().duration),
+  };
+}"""
+
+
+async def probe(config):
+    from camoufox.async_api import AsyncCamoufox
+
+    async with AsyncCamoufox(headless=True, os="linux", config=config,
+                             i_know_what_im_doing=True,
+                             executable_path=str(resolve_binary())) as browser:
+        page = await browser.new_page()
+        await page.set_content("<body></body>")
+        return await page.evaluate(PROBE)
+
+
+async def main() -> int:
+    passed = True
+    for config, expected in (({}, {"animation": 1000, "transition": [500]}),
+                             ({"instantAnimations": True}, {"animation": 0, "transition": [0]})):
+        label = "instantAnimations" if config else "default"
+        got = await probe(dict(config))  # the launcher fills in the dict it is given
+        if got == expected:
+            print(f"  PASS {label}: {got}")
+        else:
+            passed = False
+            print(f"  FAIL {label}: got {got}, expected {expected}")
+    return 0 if passed else 1
+
+
+if __name__ == "__main__":
+    sys.exit(asyncio.run(main()))
diff --git a/tests/patches/spoofed-voice-speaks.py b/tests/patches/spoofed-voice-speaks.py
new file mode 100644
index 0000000..0723749
--- /dev/null
+++ b/tests/patches/spoofed-voice-speaks.py
@@ -0,0 +1,78 @@
+"""
+Verify speechSynthesis.speak() on a spoofed voice behaves like a real voice.
+
+A spoofed voice has no speech engine behind it. voice-spoofing.patch used to fire
+an `error` event for it unless `voices:fakeCompletion` was set, and even then it
+fired `start` and `end` in the same instant. A real voice never errors on a plain
+utterance, and its `end` arrives after the text has been spoken. Both were tells.
+
+What PASS means:
+    * the page sees spoofed voices at all (so the check is not vacuous);
+    * speaking 25 characters on one fires `start`, then `end`, and no `error`;
+    * `end` arrives about as long after `start` as the text takes to say at
+      ~150 words per minute (2s here), not in the same tick.
+
+    python tests/patches/spoofed-voice-speaks.py
+"""
+
+import asyncio
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+from helpers import resolve_binary  # noqa: E402
+
+TEXT = "a" * 25  # 25 chars at 12.5 chars/s = 2.0s
+PROBE = """async (text) => {
+  let voices = speechSynthesis.getVoices();
+  if (!voices.length) {
+    await new Promise(r => { speechSynthesis.onvoiceschanged = r; setTimeout(r, 3000); });
+    voices = speechSynthesis.getVoices();
+  }
+  if (!voices.length) return {voices: 0};
+  const u = new SpeechSynthesisUtterance(text);
+  u.voice = voices[0];
+  const events = [];
+  const t0 = performance.now();
+  const done = new Promise(resolve => {
+    for (const type of ['start', 'end', 'error']) {
+      u.addEventListener(type, () => {
+        events.push([type, Math.round(performance.now() - t0)]);
+        if (type !== 'start') resolve();
+      });
+    }
+    setTimeout(resolve, 10000);
+  });
+  speechSynthesis.speak(u);
+  await done;
+  return {voices: voices.length, events};
+}"""
+
+
+async def main() -> int:
+    from camoufox.async_api import AsyncCamoufox
+
+    async with AsyncCamoufox(headless=True, os="windows",
+                             executable_path=str(resolve_binary())) as browser:
+        page = await browser.new_page()
+        await page.goto("about:blank")
+        got = await page.evaluate(PROBE, TEXT)
+    print(f"  {got}")
+
+    if not got["voices"]:
+        print("  FAIL: the page sees no voices, so nothing was tested")
+        return 1
+    kinds = [kind for kind, _ in got["events"]]
+    if kinds != ["start", "end"]:
+        print(f"  FAIL: expected start then end, got {kinds}")
+        return 1
+    spoken = got["events"][1][1] - got["events"][0][1]
+    if not 1500 <= spoken <= 4000:
+        print(f"  FAIL: end came {spoken}ms after start, expected about 2000ms")
+        return 1
+    print(f"  PASS: start, then end {spoken}ms later, no error")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(asyncio.run(main()))