--- a/docshell/base/nsAboutRedirector.cpp
+++ b/docshell/base/nsAboutRedirector.cpp
@@ -133,16 +133,22 @@ static const RedirEntry kRedirMap[] = {
   },
   {
     "telemetry", "chrome://global/content/aboutTelemetry.xhtml",
     nsIAboutModule::ALLOW_SCRIPT
   },
   {
     "webrtc", "chrome://global/content/aboutwebrtc/aboutWebrtc.html",
     nsIAboutModule::ALLOW_SCRIPT
+  },
+  {
+    "printpreview", "about:blank",
+    nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT |
+    nsIAboutModule::HIDE_FROM_ABOUTABOUT |
+    nsIAboutModule::URI_CAN_LOAD_IN_CHILD
   }
 };
 static const int kRedirTotal = mozilla::ArrayLength(kRedirMap);
 
 NS_IMETHODIMP
 nsAboutRedirector::NewChannel(nsIURI* aURI,
                               nsILoadInfo* aLoadInfo,
                               nsIChannel** aResult)
@@ -168,19 +174,21 @@ nsAboutRedirector::NewChannel(nsIURI* aU
       // chrome:// or resource://) then set the LOAD_REPLACE flag on the
       // channel which forces the channel owner to reflect the displayed
       // URL rather then being the systemPrincipal.
       bool isUIResource = false;
       rv = NS_URIChainHasFlags(tempURI, nsIProtocolHandler::URI_IS_UI_RESOURCE,
                                &isUIResource);
       NS_ENSURE_SUCCESS(rv, rv);
 
-      nsLoadFlags loadFlags =
-        isUIResource ? static_cast<nsLoadFlags>(nsIChannel::LOAD_NORMAL)
-                     : static_cast<nsLoadFlags>(nsIChannel::LOAD_REPLACE);
+      bool isAboutBlank = NS_IsAboutBlank(tempURI);
+
+      nsLoadFlags loadFlags = isUIResource || isAboutBlank
+                    ? static_cast<nsLoadFlags>(nsIChannel::LOAD_NORMAL)
+                    : static_cast<nsLoadFlags>(nsIChannel::LOAD_REPLACE);
 
       rv = NS_NewChannelInternal(getter_AddRefs(tempChannel),
                                  tempURI,
                                  aLoadInfo,
                                  nullptr, // aLoadGroup
                                  nullptr, // aCallbacks
                                  loadFlags);
       NS_ENSURE_SUCCESS(rv, rv);

--- a/docshell/build/nsDocShellModule.cpp
+++ b/docshell/build/nsDocShellModule.cpp
@@ -184,16 +184,17 @@ const mozilla::Module::ContractIDEntry k
   { NS_ABOUT_MODULE_CONTRACTID_PREFIX "serviceworkers", &kNS_ABOUT_REDIRECTOR_MODULE_CID },
 #ifndef ANDROID
   { NS_ABOUT_MODULE_CONTRACTID_PREFIX "profiles", &kNS_ABOUT_REDIRECTOR_MODULE_CID },
 #endif
   { NS_ABOUT_MODULE_CONTRACTID_PREFIX "srcdoc", &kNS_ABOUT_REDIRECTOR_MODULE_CID },
   { NS_ABOUT_MODULE_CONTRACTID_PREFIX "support", &kNS_ABOUT_REDIRECTOR_MODULE_CID },
   { NS_ABOUT_MODULE_CONTRACTID_PREFIX "telemetry", &kNS_ABOUT_REDIRECTOR_MODULE_CID },
   { NS_ABOUT_MODULE_CONTRACTID_PREFIX "webrtc", &kNS_ABOUT_REDIRECTOR_MODULE_CID },
+  { NS_ABOUT_MODULE_CONTRACTID_PREFIX "printpreview", &kNS_ABOUT_REDIRECTOR_MODULE_CID },
   { NS_URI_LOADER_CONTRACTID, &kNS_URI_LOADER_CID },
   { NS_DOCUMENTLOADER_SERVICE_CONTRACTID, &kNS_DOCUMENTLOADER_SERVICE_CID },
   { NS_HANDLERSERVICE_CONTRACTID, &kNS_CONTENTHANDLERSERVICE_CID, mozilla::Module::CONTENT_PROCESS_ONLY },
   { NS_EXTERNALHELPERAPPSERVICE_CONTRACTID, &kNS_EXTERNALHELPERAPPSERVICE_CID },
   { NS_EXTERNALPROTOCOLSERVICE_CONTRACTID, &kNS_EXTERNALHELPERAPPSERVICE_CID },
   { NS_MIMESERVICE_CONTRACTID, &kNS_EXTERNALHELPERAPPSERVICE_CID },
   { NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX"default", &kNS_EXTERNALPROTOCOLHANDLER_CID },
   { NS_PREFETCHSERVICE_CONTRACTID, &kNS_PREFETCHSERVICE_CID },