This post is an effort to draw attention to a regression in Tahoe that has a large impact on our app. This bug was filed during seed 3 but remains open: FB18869578: Regression: WebView fails to render fonts registered with CTFontManagerRegisterFontURLs or ATSApplicationFontsPath The gist of it is that WKWebView fails to render text that is styled with a “font-family” that references a font that has been loaded into the app using either the ATSApplicationFontsPath Info.plist key or loaded dynamically with CTFontManagerRegisterFontURLs. The area where the text should be is just blank. There is more detail and a reproducer in the bug referenced above. We really hope this bug can get fixed before GA. If anyone else would like to try and reproduce it, you can download a test case from here: https://e3supportuploads.s3-accelerate.amazonaws.com/8739959ce24de40fa462798a532aaa99fbfc9affba4f2a3e71d397f9e30d2604

It‘s called Track Configuration API found in the iOS 26.0 Public Beta 5. No explanation anywhere on the web Or release notes, it’s not mentioned anywhere. I‘m very interested in new tracking innovations. And another small thing I‘ve never found out, what is „fingerprint related quirk“ is that an insider joke Or something? I don‘t know it‘s actions. Thank you for answering

This is my first post, so please forgive me if it is to the wrong area. I've been using Tahoe for a few days and, overall, it's very stable. But the one thing that has bothered me to no end is Safari's new behavior with respect to its header (Address bar, Favorite bookmarks bar, tab bar) background color. The web content of the active tab seems to affect everything - and oftentimes makes things completely unreadable - at least in "Dark" mode. For instance, if a web page uses a white background, the Favorites bookmark labels are the same color as the bookmark background, so reading the labels is simply impossible. At other times, they're just very difficult to read. Similarly, it is almost always impossible to tell which tab is the active one - my only workaround is to try 100% brightness....or to just guess. When Apple previously experimented with letting content bleed through to the top, there was a setting for stopping it - but I don't see such a setting anymore. Do you you know of any way to stop this effect?

An Administrator account is executing safaridriver --enable but it doesn't apply to other standard user accounts and standard accounts can't enable it directly. Is this expected behavior? How can standard users make use of safaridriver?

Hi there, I'm experiencing several crashes on JavaScriptCore pas_panic_on_out_of_memory_error, only on devices with tvOS 15.4 and 15.4.1. This happens with users using the app for several hours as well as 5 seconds after launching the app. Devices: AppleTV6,2 and AppleTV5,3 Thread 14 — JavaScriptCore pas_panic_on_out_of_memory_error (JavaScriptCore) JavaScriptCore bmalloc_try_iso_allocate_impl_impl_slow (JavaScriptCore) JavaScriptCore bmalloc_heap_config_specialized_local_allocator_try_allocate_small_segregated_slow (JavaScriptCore) JavaScriptCore bmalloc_allocate_impl_casual_case (JavaScriptCore) JavaScriptCore ***::String::String(char16_t const*, unsigned int) (JavaScriptCore) JavaScriptCore JSC::LiteralParser<char16_t>::parsePrimitiveValue(JSC::VM&) (JavaScriptCore) JavaScriptCore JSC::LiteralParser<char16_t>::parse(JSC::ParserState) (JavaScriptCore) JavaScriptCore JSC::jsonProtoFuncParse(JSC::JSGlobalObject*, JSC::CallFrame*) (JavaScriptCore) JavaScriptCore llint_entry (JavaScriptCore) JavaScriptCore llint_entry (JavaScriptCore) JavaScriptCore llint_entry (JavaScriptCore) JavaScriptCore llint_entry (JavaScriptCore) JavaScriptCore vmEntryToJavaScript (JavaScriptCore) JavaScriptCore JSC::Interpreter::executeCall(JSC::JSGlobalObject*, JSC::JSObject*, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) (JavaScriptCore) JavaScriptCore JSC::boundThisNoArgsFunctionCall(JSC::JSGlobalObject*, JSC::CallFrame*) (JavaScriptCore) JavaScriptCore vmEntryToNative (JavaScriptCore) JavaScriptCore JSC::Interpreter::executeCall(JSC::JSGlobalObject*, JSC::JSObject*, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) (JavaScriptCore) JavaScriptCore JSC::profiledCall(JSC::JSGlobalObject*, JSC::ProfilingReason, JSC::JSValue, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) (JavaScriptCore) JavaScriptCore JSObjectCallAsFunction (JavaScriptCore) JavaScriptCore -[JSValue invokeMethod:withArguments:] (JavaScriptCore) ITMLKit -[IKJSObject invokeMethod:withArguments:] (ITMLKit) ITMLKit -[IKJSEventListenerObject invokeMethod:withArguments:thenDispatchEvent:extraInfo:] (ITMLKit) ITMLKit __43-[IKJSXMLHTTPRequest setRequestReadyState:]_block_invoke (ITMLKit) ITMLKit -[IKAppContext _doEvaluate:] (ITMLKit) ITMLKit -[IKAppContext _evaluate:] (ITMLKit) ITMLKit __41-[IKAppContext evaluate:completionBlock:]_block_invoke (ITMLKit) ITMLKit -[IKAppContext _sourcePerform] (ITMLKit) ITMLKit -[IKConcurrentEvaluator lockSchedulingForEvaluation:] (ITMLKit) ITMLKit IKRunLoopSourcePerformCallBack (ITMLKit) CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ (CoreFoundation) CoreFoundation __CFRunLoopDoSource0 (CoreFoundation) CoreFoundation __CFRunLoopDoSources0 (CoreFoundation) CoreFoundation __CFRunLoopRun (CoreFoundation) CoreFoundation CFRunLoopRunSpecific (CoreFoundation) ITMLKit -[IKAppContext _jsThreadMain] (ITMLKit) Foundation __NSThread__start__ (Foundation) libsyste...ad.dylib _pthread_start (libsystem_pthread.dylib) libsyste...ad.dylib thread_start (libsystem_pthread.dylib) This issue seems very similar to this existing thread, although not sure its related

In a Safari Web Extension using Manifest V3, how can a content script access an HTML file that is bundled with the extension (e.g., to inject it as an iframe)? Safari's CSP seem to prevent the use of browser.runtime.getURL() in the MAIN world — is there a recommended way to load such resources securely?

I’m experiencing a crash in WKWebView on iOS 26 Developer Beta 5 and Beta 6 with the following exception: CALayer position contains NaN: [nan 65] The crash occurs when the following CSS properties are applied to content displayed in WKWebView: -webkit-user-select: none; -webkit-touch-callout: none; This issue happens consistently whenever these styles are set, leading to the crash inside WKWebView. Is this a known bug in the current iOS 26 betas, or is there a recommended workaround?

Hi, I’m working with the SFExtensionProfileKey in my Safari Web Extension. As I understand it, this key is to get the UUID of the profile currently in use. However, it seems to be missing (no key in userInfo) when the default profile is active. Also, I haven’t found any API to get a profile’s human-readable name or list all available profiles. Could someone clarify: If the value of SFExtensionProfileKey is absent, can I safely assume the default profile is in use? Is there a supported way to get a profile’s display name? Does Safari expose an API for getting all profiles? Thanks in advance for your insights!

I'm working on a Safari web extension that uses the nativeMessaging facility to communication with native code. When I want to notify the javascript extension from the embedding application, I use SFSafariApplication::dispatchMessage. As per the documentation, this call ... ensures that Safari is launched and that your extension is running before delivering the message. Everything works fine when the background script is running. However, after the background script gets unloaded at some point in time (non persistent background page, default behavior for a manifest V3 extension), the background script is not reloaded by the message from the native app (background script still appears unloaded in the developer menu of Safari, double-checked using a counter stored in browser.storage.local incremented on message reception). In this case, the completion handler of the application gets no error (error == nil) as if the message was correctly delivered. I was able to reproduce this behavior with the sample app delivered for WWDC20 (after upgrading the manifest from v2 to v3 to make it non-persistent). Is it supposed to work ? What I'm doing wrong ?

Hi all, Managing Safari usage in an enterprise environment and I’m looking for ways to disable or restrict the QUIC protocol to enforce network-level security policies (e.g., content filtering). Does Safari offer any settings to disable QUIC, or is there a known workaround to prevent Safari from using it? Appreciate any insights or guidance.

We are building a hybrid iOS app using Angular (web) rendered inside a WKWebView, hosted by a native Swift app. Communication between the Angular UI and native Swift code is done using WKScriptMessageHandler. The app mostly works without issues, but in rare edge cases, we’re seeing crashes on the main thread, and the crash is reported in Firebase Crashlytics. The root cause appears related to CFRelease and WKScriptMessageHandler. Here’s the relevant crash stack: Crashed: com.apple.main-thread 0 CoreFoundation 0xbfac CFRelease + 44 1 CoreFoundation 0xa734 __CFURLDeallocate + 128 2 CoreFoundation 0x730c _CFRelease + 292 3 libobjc.A.dylib 0x4e28 AutoreleasePoolPage::releaseUntil(objc_object**) + 204 4 libobjc.A.dylib 0x4cbc objc_autoreleasePoolPop + 260 5 WebKit 0x99f194 WebKit::WebUserContentControllerProxy::didPostMessage(WTF::ObjectIdentifierGeneric<WebKit::WebPageProxyIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long long>, unsigned long long>, WebKit::FrameInfoData&&, WTF::ObjectIdentifierGeneric<WebKit::ScriptMessageHandlerIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long long>, unsigned long long>, std::__1::span<unsigned char const, 18446744073709551615ul>, WTF::CompletionHandler<void (std::__1::span<unsigned char const, 18446744073709551615ul>, WTF::String const&)>&&) + 680 6 WebKit 0x1b358 WebKit::WebUserContentControllerProxy::didReceiveMessage(IPC::Connection&, IPC::Decoder&) + 392 7 WebKit 0xe86b0 IPC::MessageReceiverMap::dispatchMessage(IPC::Connection&, IPC::Decoder&) + 272 8 WebKit 0x23c0c WebKit::WebProcessProxy::didReceiveMessage(IPC::Connection&, IPC::Decoder&) + 44 9 WebKit 0xe3f054 IPC::Connection::dispatchMessage(WTF::UniqueRef<IPC::Decoder>) + 252 10 WebKit 0x332d4 IPC::Connection::dispatchIncomingMessages() + 744 11 JavaScriptCore 0x58a7c WTF::RunLoop::performWork() + 204 12 JavaScriptCore 0x599a4 WTF::RunLoop::performWork(void*) + 36 13 CoreFoundation 0x56328 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28 14 CoreFoundation 0x562bc __CFRunLoopDoSource0 + 176 15 CoreFoundation 0x53dc0 __CFRunLoopDoSources0 + 244 16 CoreFoundation 0x52fbc __CFRunLoopRun + 840 17 CoreFoundation 0x52830 CFRunLoopRunSpecific + 588 18 GraphicsServices 0x11c4 GSEventRunModal + 164 19 UIKitCore 0x3d2eb0 -[UIApplication _run] + 816 20 UIKitCore 0x4815b4 UIApplicationMain + 340 21 APP1 0xa2f80 main + 21 (AppDelegate.swift:21) 22 ??? 0x1c234eec8 (シンボルが不足しています) Steps: WebView: WKWebView Message passing: WKScriptMessageHandler → passing data from Angular → Swift WKWebView is long-lived and reused Native is using WKUserContentController.add(_:name:) to register handlers Crashes are intermittent (hard to reproduce), but often follow: Screen sleep/wake Push notification open Angular calling native immediately after resume Questions: Has anyone seen this specific crash pattern involving CFRelease and WKScriptMessageHandler? Are there known WebKit or CoreFoundation bugs related to WKScriptMessageHandler and retained URLs or message content? Thank you for your help!

I have compiled some Java code to WebAssembly via TeaVM and wrapped it in a PWA. The resulting code runs nicely in Firefox and Chrome but throws an exception in Safari. CompileError: WebAssembly.Module doesn't parse at byte 1657: invalid extended GC op 24, in function at index 2251 Can anybody tell me what's wrong with that code? I mean it can't be so bad if Firefox and Chrome can parse and run it without problems. I am using the most recent versions of all browsers and the offending code can be found here: Run the demo via: https://mpmediasoft.de/demos/Emmentaler/Emmentaler-Demo-TeaVM-Wasm/index.html The offending wasm file is: https://mpmediasoft.de/demos/Emmentaler/Emmentaler-Demo-TeaVM-Wasm/tvw/ModelBridgeTeaVM.wasm With Safari the demo just shows some empty space instead of a complex polygon. You can see the error in the javascript console of Safari.

I am new to PHP. I have developed my own web site with a lot of javascript in simple HTML files. I want to do some extensions with PHP but I can't make a simple web page function. I am sure something simple is wrong. Help! Here is the test web page I made: hello.html <html>  <head>   <title>Hello World</title>  </head>  <body>   <?php echo 'Hello World!'; ?>  </body> </html> Pointing Safari at hello.html gives me a new tab with the correct title, but no "Hello World" in the page itself. Here is the output of php --version: WARNING: PHP is not recommended PHP is included in macOS for compatibility with legacy software. Future versions of macOS will not include PHP. PHP 7.3.24-(to be removed in future macOS) (cli) (built: Jun 17 2021 21:41:13) ( NTS ) Copyright (c) 1997-2018 The PHP Group Zend Engine v3.3.24, Copyright (c) 1998-2018 Zend Technologies

Environment • Device: any iPhone running iOS 26 Developer Beta 5 (23A5308g) • Xcode: 16.3 Short description The app crashes the moment the user tries to long-press to select text inside a WKWebView, double-tap an image with Text (magnifier appears) The exception is CALayer position contains NaN. frame = (nan,0;0,48) chorPoint=(inf, 0) and it is thrown in the UI process. Build & run any project that hosts a WKWebView. Inject the following CSS via script (this is what we do to suppress the native callout menu): WKWebView *webView = [[WKWebView alloc] initWithFrame:self.view.bounds configuration:[WKWebViewConfiguration new]]; NSString *js = @"document.documentElement.style.webkitUserSelect='none';" "document.documentElement.style.webkitTouchCallout='none';"; [webView evaluateJavaScript:js completionHandler:nil]; [self.view addSubview:webView]; Incident Identifier: EE6FB046-5087-4F15-A72D-A74965347A30 CrashReporter Key: 29e8e58e02a07557adb4ce3f463d764f3ce8bbd5 Hardware Model: iPhone16,1 Process: wallet [642] Path: /private/var/containers/Bundle/Application/4B4E609A-C8BF-4C56-AB2A-1638249B98A5/wallet.app/wallet Identifier: xxxxxxx Version: xxxx AppStoreTools: 16F7 AppVariant: 1:iPhone16,1:18 Code Type: ARM-64 (Native) Role: Foreground Parent Process: launchd [1] Coalition: xxxxxx Date/Time: 2025-08-06 12:05:24.0732 +0800 Launch Time: 2025-08-06 11:49:40.3802 +0800 OS Version: iPhone OS 26.0 (23A5308g) Release Type: Beta Baseband Version: 3.02.02 Report Version: 104 Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Termination Reason: SIGNAL 6 Abort trap: 6 Terminating Process: wallet [642] Triggered by Thread: 0 Application Specific Information: abort() called Thread 0 Crashed: 0 libsystem_kernel.dylib 0x22da0f0cc __pthread_kill + 8 1 libsystem_pthread.dylib 0x1e097b7e8 pthread_kill + 268 2 libsystem_c.dylib 0x191361f1c abort + 124 3 libc++abi.dylib 0x182e7a808 __abort_message + 132 4 libc++abi.dylib 0x182e69484 demangling_terminate_handler() + 304 5 libobjc.A.dylib 0x182d7bf28 _objc_terminate() + 156 6 wallet 0x1068ff8c8 0x1046f4000 + 35698888 7 libc++abi.dylib 0x182e79bdc std::__terminate(void (*)()) + 16 8 libc++abi.dylib 0x182e7d314 __cxxabiv1::failed_throw(__cxxabiv1::__cxa_exception*) + 88 9 libc++abi.dylib 0x182e7d2bc __cxa_throw + 92 10 libobjc.A.dylib 0x182d7992c objc_exception_throw + 448 11 CoreFoundation 0x185e908d4 +[NSException raise:format:] + 128 12 QuartzCore 0x18678a874 CA::Layer::set_position(CA::Vec2<double> const&, bool) + 160 13 QuartzCore 0x1869a7270 -[CALayer setPosition:] + 52 14 UIKitCore 0x18c4ac564 -[UIView _backing_setPosition:] + 176 15 UIKitCore 0x18cefdf0c -[UIView setCenter:] + 220 16 UIKitCore 0x18cd9f794 -[_UIEditMenuContentPresentation _displayPreparedMenu:titleView:reason:didDismissMenu:configuration:] + 936 17 UIKitCore 0x18cd9f3c0 __54-[_UIEditMenuContentPresentation _displayMenu:reason:]_block_invoke + 104 18 UIKitCore 0x18ced1060 -[UIEditMenuInteraction _editMenuPresentation:preparedMenuForDisplay:completion:] + 384 19 UIKitCore 0x18cd9f2e4 -[_UIEditMenuContentPresentation _displayMenu:reason:] + 304 20 UIKitCore 0x18cd9f0d8 -[_UIEditMenuContentPresentation displayMenu:configuration:] + 64 21 UIKitCore 0x18ced0344 __58-[UIEditMenuInteraction presentEditMenuWithConfiguration:]_block_invoke + 260 22 UIKitCore 0x18ced1f8c __80-[UIEditMenuInteraction _prepareMenuAtLocation:configuration:completionHandler:]_block_invoke + 80 23 UIKitCore 0x18cc8403c __109-[UITextContextMenuInteraction _editMenuInteraction:menuForConfiguration:suggestedActions:completionHandler:]_block_invoke + 180 24 UIKitCore 0x18cc84584 __107-[UITextContextMenuInteraction _querySelectionCommandsForConfiguration:suggestedActions:completionHandler:]_block_invoke + 148 25 WebKit 0x1a05ae5d4 WTF::CompletionHandler<void (WebKit::DocumentEditingContext&&)>::operator()(WebKit::DocumentEditingContext&&) + 64 26 WebKit 0x1a05bb468 WTF::Detail::CallableWrapper<WTF::CompletionHandler<void (IPC::Connection*, IPC::Decoder*)> IPC::Connection::makeAsyncReplyCompletionHandler<Messages::WebPage::RequestDocumentEditingContext, WTF::CompletionHandler<void (WebKit::DocumentEditingContext&&)>>(WTF::CompletionHandler<void (WebKit::DocumentEditingContext&&)>&&, WTF::ThreadLikeAssertion)::'lambda'(IPC::Connection*, IPC::Decoder*), void, IPC::Connection*, IPC::Decoder*>::call(IPC::Connection*, IPC::Decoder*) + 196 27 WebKit 0x19fcf5db8 WTF::Detail::CallableWrapper<WebKit::AuxiliaryProcessProxy::sendMessage(WTF::UniqueRef<IPC::Encoder>&&, WTF::OptionSet<IPC::SendOption>, std::__1::optional<IPC::ConnectionAsyncReplyHandler>, WebKit::AuxiliaryProcessProxy::ShouldStartProcessThrottlerActivity)::$_1, void, IPC::Connection*, IPC::Decoder*>::call(IPC::Connection*, IPC::Decoder*) + 64 28 WebKit 0x19fce54f0 IPC::Connection::dispatchMessage(WTF::UniqueRef<IPC::Decoder>) + 340 29 WebKit 0x19fcf5aa0 IPC::Connection::dispatchIncomingMessages() + 536 30 JavaScriptCore 0x19a8f85d4 WTF::RunLoop::performWork() + 552 31 JavaScriptCore 0x19a8f838c WTF::RunLoop::performWork(void*) + 36 32 CoreFoundation 0x185da6230 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28 33 CoreFoundation 0x185da61a4 __CFRunLoopDoSource0 + 172 34 CoreFoundation 0x185d83c6c __CFRunLoopDoSources0 + 232 35 CoreFoundation 0x185d598b0 __CFRunLoopRun + 820 36 CoreFoundation 0x185d58c44 _CFRunLoopRunSpecificWithOptions + 532 37 GraphicsServices 0x224ce0498 GSEventRunModal + 120 38 UIKitCore 0x18b6c84b8 -[UIApplication _run] + 792 39 UIKitCore 0x18b66cbc0 UIApplicationMain + 336 40 wallet 0x1046f8558 0x1046f4000 + 17752 41 dyld 0x182dcdb18 start + 6332

Hi! I'm working on a web extension for Safari and I need to send messages from the containing application to JavaScript. For this I use the method class func dispatchMessage( withName messageName: String, toExtensionWithIdentifier identifier: String, userInfo: [String : Any]? = nil ) async throws of the SFSafariApplication class. If the site is opened in Safari in normal mode, everything works as expected. However, if the site is "docked", the messages are not transmitted to this "Web App".

//Is my post method correct because google and claude are telling me I must use content type for the json and use .setvalue. I thought that my process was correct because I encode the data to turn into json and then make the request func createTask(_ task: Task) async throws -> Task { if let url = URL(string: "(baseURL)/todos"){ var request = URLRequest(url: url) request.httpMethod = "POST" let encoder = JSONEncoder() do{ let data = try encoder.encode(task) request.httpBody = data let (data, response) = try await URLSession.shared.data(for: request) return task //we want to make encoder and then turn the data into json and put it in body } catch{ throw JSONErrors.encodingFailed } } else{ throw URLError(.badURL) } }

There is webview use in native MacOS app, there white lines on edges of webview you can observe, they are flickering if do resize the app window. i would like to get rid of them. i need help, thanks.

Area: WebKit (Safari) Description: I am reporting an issue where our application's core functionality is being broken by Safari's Intelligent Tracking Prevention (ITP). ITP's "Link Tracking Protection" feature automatically strips specific query parameters from URLs. We understand this is an intentional privacy feature. However, our application requires these query parameters to carry essential, non-tracking data, such as authentication tokens or specific app-state information to function correctly. When a user navigates to our site, Safari strips these parameters, this means our client-side application never receives the necessary data, which breaks core features and leads to a failed user experience. This is a significant issue for our application as it prevents users from accessing their content. We are seeking guidance on how to resolve this. Questions for Apple: Is there a recommended way to identify and flag essential, non-tracking query parameters so that Safari's ITP does not strip them? Our parameters are critical for app functionality, not for third-party tracking. What is the recommended best practice for building web applications that rely on URL parameters while adhering to ITP's privacy-first model? We want to ensure our application is compatible with modern browser privacy features without compromising functionality. Could you provide a detailed explanation of what criteria ITP uses to decide which parameters to strip? Understanding the underlying logic would help us restructure our URLs to avoid this issue. Device Information: Operating System: iOS and macOS Safari Version: Latest stable versions on both platforms Device Models: All relevant models and device types

Since the transition to iOS 18.4, we have been having an issue where when loading an m3u8 file specified in the src attribute of a video tag in WKWebView, the ts file is loaded repeatedly. Are there any good ideas for this? Also, if there have been any changes to the specifications of WKWebView, we would appreciate it if you could let us know.

I'm trying to use DNR to force safe search with Qwant search engine. Under certain circumstances (scenario described below) the search is performed with an API which contains the safe search level in a URL parameter. A typical query URL is https://api.qwant.com/v3/search/web?q=test&count=10&locale=fr_FR&offset=0&device=desktop&tgp=1&safesearch=0&displayed=true&llm=true. I want a DNR rule to force safesearch to be 2 (= strict) (from some javascript code) : { id: 1, priority: 1, action: { type: 'redirect', "redirect": { "transform": { "queryTransform": { "addOrReplaceParams": [{ "key": "safesearch", "value": "2" }] } } } }, condition: { "urlFilter": "api.qwant.com/v3/search", "resourceTypes": ["xmlhttprequest"] }, } When this rule is activated, I end up with a URL with the original safesearch parameter AND the forced one : https://api.qwant.com/v3/search/web?q=test&count=10&locale=fr_FR&offset=0&device=desktop&tgp=1&safesearch=0&displayed=true&llm=true&safesearch=2. To reproduce this request (with the previous DNR rule in place) : navigate to https://www.qwant.com search for some string (test in my case). This displays the list of results ; click the engine button at the top right to display the settings pane ; inspect network request performed by this page ; change the Adult filter in the list -> the results are automatically updated with the new settings. The web request shows URL with the 2 safesearch parameters. I already used addOrReplaceParams in 'standard' contexts (main_frame) and it works just fine. Any hint on what goes on ? Thank you.