diff --git a/dom/base/Navigator.cpp b/dom/base/Navigator.cpp
index c6e3e16f4e49..8fa619d79a97 100644
--- a/dom/base/Navigator.cpp
+++ b/dom/base/Navigator.cpp
@@ -985,7 +985,6 @@ void Navigator::CheckProtocolHandlerAllowed(const nsAString& aScheme,
 
 void Navigator::RegisterProtocolHandler(const nsAString& aScheme,
                                         const nsAString& aURI,
-                                        const nsAString& aTitle,
                                         ErrorResult& aRv) {
   if (!mWindow || !mWindow->GetOuterWindow() || !mWindow->GetDocShell() ||
       !mWindow->GetDoc()) {
@@ -1014,9 +1013,13 @@ void Navigator::RegisterProtocolHandler(const nsAString& aScheme,
     return;
   }
 
+  // Determine a title from the document URI.
+  nsAutoCString docDisplayHostPort;
+  docURI->GetDisplayHostPort(docDisplayHostPort);
+  NS_ConvertASCIItoUTF16 title(docDisplayHostPort);
+
   if (XRE_IsContentProcess()) {
     nsAutoString scheme(aScheme);
-    nsAutoString title(aTitle);
     RefPtr<BrowserChild> browserChild = BrowserChild::GetFrom(mWindow);
     browserChild->SendRegisterProtocolHandler(scheme, handlerURI, title,
                                               docURI);
@@ -1026,8 +1029,8 @@ void Navigator::RegisterProtocolHandler(const nsAString& aScheme,
   nsCOMPtr<nsIWebProtocolHandlerRegistrar> registrar =
       do_GetService(NS_WEBPROTOCOLHANDLERREGISTRAR_CONTRACTID);
   if (registrar) {
-    aRv = registrar->RegisterProtocolHandler(aScheme, handlerURI, aTitle,
-                                             docURI, mWindow->GetOuterWindow());
+    aRv = registrar->RegisterProtocolHandler(aScheme, handlerURI, title, docURI,
+                                             mWindow->GetOuterWindow());
   }
 }
 
diff --git a/dom/base/Navigator.h b/dom/base/Navigator.h
index 9e898052f8ee..043fa07e152c 100644
--- a/dom/base/Navigator.h
+++ b/dom/base/Navigator.h
@@ -123,7 +123,7 @@ class Navigator final : public nsISupports, public nsWrapperCache {
                                    nsIURI* aHandlerURI, nsIURI* aDocumentURI,
                                    ErrorResult& aRv);
   void RegisterProtocolHandler(const nsAString& aScheme, const nsAString& aURL,
-                               const nsAString& aTitle, ErrorResult& aRv);
+                               ErrorResult& aRv);
   nsMimeTypeArray* GetMimeTypes(ErrorResult& aRv);
   nsPluginArray* GetPlugins(ErrorResult& aRv);
   Permissions* GetPermissions(ErrorResult& aRv);
diff --git a/dom/webidl/Navigator.webidl b/dom/webidl/Navigator.webidl
index 1bf3cf7e843e..5382bc56c8c6 100644
--- a/dom/webidl/Navigator.webidl
+++ b/dom/webidl/Navigator.webidl
@@ -84,7 +84,7 @@ interface mixin NavigatorContentUtils {
   [Throws, ChromeOnly]
   void checkProtocolHandlerAllowed(DOMString scheme, URI handlerURI, URI documentURI);
   [Throws, SecureContext]
-  void registerProtocolHandler(DOMString scheme, DOMString url, DOMString title);
+  void registerProtocolHandler(DOMString scheme, DOMString url);
   // NOT IMPLEMENTED
   //void unregisterProtocolHandler(DOMString scheme, DOMString url);
 };
diff --git a/testing/web-platform/meta/html/dom/idlharness.https.html.ini b/testing/web-platform/meta/html/dom/idlharness.https.html.ini
index a44aac102fa3..936536f61e5a 100644
--- a/testing/web-platform/meta/html/dom/idlharness.https.html.ini
+++ b/testing/web-platform/meta/html/dom/idlharness.https.html.ini
@@ -711,9 +711,6 @@ prefs: [dom.security.featurePolicy.experimental.enabled:true, dom.security.featu
   [OffscreenCanvasRenderingContext2D interface: operation arc(unrestricted double, unrestricted double, unrestricted double, unrestricted double, unrestricted double, optional boolean)]
     expected: FAIL
 
-  [Navigator interface: operation registerProtocolHandler(DOMString, USVString)]
-    expected: FAIL
-
   [ElementInternals interface: operation setValidity(optional ValidityStateFlags, optional DOMString, optional HTMLElement)]
     expected: FAIL
 
diff --git a/testing/web-platform/meta/html/webappapis/system-state-and-capabilities/the-navigator-object/historical.https.window.js.ini b/testing/web-platform/meta/html/webappapis/system-state-and-capabilities/the-navigator-object/historical.https.window.js.ini
deleted file mode 100644
index 28f62390271f..000000000000
--- a/testing/web-platform/meta/html/webappapis/system-state-and-capabilities/the-navigator-object/historical.https.window.js.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[historical.https.window.html]
-  [registerProtocolHandler has no third argument]
-    expected: FAIL
-