diff --git a/mozilla/chrome/src/nsChromeProtocolHandler.cpp b/mozilla/chrome/src/nsChromeProtocolHandler.cpp
index 7495c80389f..36ee9e0f481 100644
--- a/mozilla/chrome/src/nsChromeProtocolHandler.cpp
+++ b/mozilla/chrome/src/nsChromeProtocolHandler.cpp
@@ -327,7 +327,7 @@ nsCachedChromeChannel::SetNotificationCallbacks(nsIInterfaceRequestor * aNotific
 NS_IMETHODIMP 
 nsCachedChromeChannel::GetContentType(char * *aContentType)
 {
-    *aContentType = nsXPIDLCString::Copy("text/cached-xul");
+    *aContentType = nsXPIDLCString::Copy("mozilla.application/cached-xul");
     return *aContentType ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
 }
 
diff --git a/mozilla/content/build/nsContentDLF.cpp b/mozilla/content/build/nsContentDLF.cpp
index af12814b443..a7b8fd32b50 100644
--- a/mozilla/content/build/nsContentDLF.cpp
+++ b/mozilla/content/build/nsContentDLF.cpp
@@ -73,8 +73,8 @@ static char* gXMLTypes[] = {
 
 static char* gRDFTypes[] = {
   "text/rdf",
-  "text/xul",
-  "text/cached-xul",
+  "application/vnd.mozilla.xul+xml",
+  "mozilla.application/cached-xul",
   0
 };
 
diff --git a/mozilla/content/build/nsContentModule.cpp b/mozilla/content/build/nsContentModule.cpp
index e3c618b3970..206d1b3cb5b 100644
--- a/mozilla/content/build/nsContentModule.cpp
+++ b/mozilla/content/build/nsContentModule.cpp
@@ -339,7 +339,7 @@ static Components gComponents[] = {
   { "HTML content serializer", NS_HTMLCONTENTSERIALIZER_CID,
     NS_CONTENTSERIALIZER_CONTRACTID_PREFIX "text/html", },
   { "XUL content serializer", NS_XMLCONTENTSERIALIZER_CID,
-    NS_CONTENTSERIALIZER_CONTRACTID_PREFIX "text/xul", },
+    NS_CONTENTSERIALIZER_CONTRACTID_PREFIX "application/vnd.mozilla.xul+xml", },
   { "plaintext content serializer", NS_PLAINTEXTSERIALIZER_CID,
     NS_CONTENTSERIALIZER_CONTRACTID_PREFIX "text/plain", },
   { "plaintext sink", NS_PLAINTEXTSERIALIZER_CID,
diff --git a/mozilla/content/xul/document/src/nsXULDocument.cpp b/mozilla/content/xul/document/src/nsXULDocument.cpp
index 1a90b517417..ae2e2523447 100644
--- a/mozilla/content/xul/document/src/nsXULDocument.cpp
+++ b/mozilla/content/xul/document/src/nsXULDocument.cpp
@@ -613,7 +613,7 @@ nsXULDocument::GetArena()
 NS_IMETHODIMP
 nsXULDocument::GetContentType(nsAWritableString& aContentType) const
 {
-    aContentType.Assign(NS_LITERAL_STRING("text/xul"));
+    aContentType.Assign(NS_LITERAL_STRING("application/vnd.mozilla.xul+xml"));
     return NS_OK;
 }
 
@@ -707,7 +707,8 @@ nsXULDocument::StartDocumentLoad(const char* aCommand,
     nsXPIDLCString contentType;
     aChannel->GetContentType(getter_Copies(contentType));
 
-    if (contentType && PL_strcmp(contentType, "text/cached-xul") == 0) {
+    if (contentType && 
+        PL_strcmp(contentType, "mozilla.application/cached-xul") == 0) {
         // Look in the chrome cache: we've got this puppy loaded
         // already.
         nsCOMPtr<nsIXULPrototypeDocument> proto;
diff --git a/mozilla/docshell/base/nsDSURIContentListener.cpp b/mozilla/docshell/base/nsDSURIContentListener.cpp
index af965962ef1..d3c14d18ff1 100644
--- a/mozilla/docshell/base/nsDSURIContentListener.cpp
+++ b/mozilla/docshell/base/nsDSURIContentListener.cpp
@@ -152,7 +152,7 @@ NS_IMETHODIMP nsDSURIContentListener::CanHandleContent(const char* aContentType,
   // from the registry and in addition, we want to
   //    incoming Type                     Preferred type
   //      text/html
-  //      text/xul
+  //      application/vnd.mozilla.xul+xml
   //      text/rdf
   //      text/xml
   //      text/css
@@ -161,14 +161,14 @@ NS_IMETHODIMP nsDSURIContentListener::CanHandleContent(const char* aContentType,
   //      image/png
   //      image/tiff
   //      application/http-index-format
-  //      message/rfc822                    text/xul 
+  //      message/rfc822                    application/vnd.mozilla.xul+xml 
 
   if (aContentType)
   {
      // (1) list all content types we want to  be the primary handler for....
      // and suggest a desired content type if appropriate...
      if (nsCRT::strcasecmp(aContentType,  "text/html") == 0
-       || nsCRT::strcasecmp(aContentType, "text/xul") == 0
+       || nsCRT::strcasecmp(aContentType, "application/vnd.mozilla.xul+xml") == 0
        || nsCRT::strcasecmp(aContentType, "text/rdf") == 0 
        || nsCRT::strcasecmp(aContentType, "text/xml") == 0
        || nsCRT::strcasecmp(aContentType, "text/css") == 0
diff --git a/mozilla/embedding/browser/gtk/src/EmbedContentListener.cpp b/mozilla/embedding/browser/gtk/src/EmbedContentListener.cpp
index c1f900ad156..202eb9b7b72 100644
--- a/mozilla/embedding/browser/gtk/src/EmbedContentListener.cpp
+++ b/mozilla/embedding/browser/gtk/src/EmbedContentListener.cpp
@@ -96,7 +96,7 @@ EmbedContentListener::IsPreferred(const char        *aContentType,
   if (aContentType &&
       (!strcasecmp(aContentType, "text/html")   ||
        !strcasecmp(aContentType, "text/plain")  ||
-       !strcasecmp(aContentType, "text/xul")    ||
+       !strcasecmp(aContentType, "application/vnd.mozilla.xul+xml")    ||
        !strcasecmp(aContentType, "text/rdf")    ||
        !strcasecmp(aContentType, "text/xml")    ||
        !strcasecmp(aContentType, "text/css")    ||
diff --git a/mozilla/embedding/browser/photon/src/PhMozEmbedChrome.cpp b/mozilla/embedding/browser/photon/src/PhMozEmbedChrome.cpp
index 44c91666082..9b51bd17003 100644
--- a/mozilla/embedding/browser/photon/src/PhMozEmbedChrome.cpp
+++ b/mozilla/embedding/browser/photon/src/PhMozEmbedChrome.cpp
@@ -501,7 +501,7 @@ NS_IMETHODIMP PhMozEmbedChrome::IsPreferred(const char *aContentType, nsURILoadC
   {
     PR_LOG(mozEmbedLm, PR_LOG_DEBUG, ("checking content type %s\n", aContentType));
     if (nsCRT::strcasecmp(aContentType,  "text/html") == 0
-        || nsCRT::strcasecmp(aContentType, "text/xul") == 0
+        || nsCRT::strcasecmp(aContentType, "application/vnd.mozilla.xul+xml") == 0
         || nsCRT::strcasecmp(aContentType, "text/rdf") == 0 
         || nsCRT::strcasecmp(aContentType, "text/xml") == 0
         || nsCRT::strcasecmp(aContentType, "text/css") == 0
diff --git a/mozilla/embedding/browser/webBrowser/nsWBURIContentListener.cpp b/mozilla/embedding/browser/webBrowser/nsWBURIContentListener.cpp
index 72cf6bce23c..aced3778173 100644
--- a/mozilla/embedding/browser/webBrowser/nsWBURIContentListener.cpp
+++ b/mozilla/embedding/browser/webBrowser/nsWBURIContentListener.cpp
@@ -122,7 +122,7 @@ NS_IMETHODIMP nsWBURIContentListener::IsPreferred(const char* aContentType,
    // regardlesss of the uri load command.
    //    incoming Type                     Preferred type
    //      text/html
-   //      text/xul
+   //      application/vnd.mozilla.xul+xml
    //      text/rdf
    //      text/xml
    //      text/css
@@ -137,7 +137,7 @@ NS_IMETHODIMP nsWBURIContentListener::IsPreferred(const char* aContentType,
       // (1) list all content types we want to  be the primary handler for....
       // and suggest a desired content type if appropriate...
       if(nsCRT::strcasecmp(aContentType,  "text/html") == 0
-         || nsCRT::strcasecmp(aContentType, "text/xul") == 0
+         || nsCRT::strcasecmp(aContentType, "application/vnd.mozilla.xul+xml") == 0
          || nsCRT::strcasecmp(aContentType, "text/rdf") == 0 
          || nsCRT::strcasecmp(aContentType, "text/xml") == 0
          || nsCRT::strcasecmp(aContentType, "text/css") == 0
diff --git a/mozilla/gfx/src/nsImageNetContextAsync.cpp b/mozilla/gfx/src/nsImageNetContextAsync.cpp
index 408794e691c..b3f45ec229a 100644
--- a/mozilla/gfx/src/nsImageNetContextAsync.cpp
+++ b/mozilla/gfx/src/nsImageNetContextAsync.cpp
@@ -251,7 +251,7 @@ ImageConsumer::CanHandleContent(const char * aContentType,
   // if we had a webshell or doc shell around, we'd pass this call
   // through to it...but we don't =(
   if (!nsCRT::strcasecmp(aContentType, "message/rfc822"))
-    *aDesiredContentType = nsCRT::strdup("text/xul");
+    *aDesiredContentType = nsCRT::strdup("application/vnd.mozilla.xul+xml");
   // since we explicilty loaded the url, we always want to handle it!
   *aCanHandleContent = PR_TRUE;
     
diff --git a/mozilla/htmlparser/src/nsIParser.h b/mozilla/htmlparser/src/nsIParser.h
index c71720044d9..410987698e1 100644
--- a/mozilla/htmlparser/src/nsIParser.h
+++ b/mozilla/htmlparser/src/nsIParser.h
@@ -354,7 +354,7 @@ const PRUnichar kNullCh           = '\0';
 
 #define kHTMLTextContentType  "text/html"
 #define kXMLTextContentType   "text/xml"
-#define kXULTextContentType   "text/xul"
+#define kXULTextContentType   "application/vnd.mozilla.xul+xml"
 #define kRDFTextContentType   "text/rdf"
 #define kXIFTextContentType   "text/xif"
 #define kPlainTextContentType "text/plain"
diff --git a/mozilla/layout/build/nsContentDLF.cpp b/mozilla/layout/build/nsContentDLF.cpp
index af12814b443..a7b8fd32b50 100644
--- a/mozilla/layout/build/nsContentDLF.cpp
+++ b/mozilla/layout/build/nsContentDLF.cpp
@@ -73,8 +73,8 @@ static char* gXMLTypes[] = {
 
 static char* gRDFTypes[] = {
   "text/rdf",
-  "text/xul",
-  "text/cached-xul",
+  "application/vnd.mozilla.xul+xml",
+  "mozilla.application/cached-xul",
   0
 };
 
diff --git a/mozilla/layout/build/nsLayoutDLF.cpp b/mozilla/layout/build/nsLayoutDLF.cpp
index b4db4fa62b1..7b5f20137ce 100644
--- a/mozilla/layout/build/nsLayoutDLF.cpp
+++ b/mozilla/layout/build/nsLayoutDLF.cpp
@@ -75,8 +75,8 @@ static char* gXMLTypes[] = {
 
 static char* gRDFTypes[] = {
   "text/rdf",
-  "text/xul",
-  "text/cached-xul",
+  "application/vnd.mozilla.xul+xml",
+  "mozilla.application/cached-xul",
   0
 };
 
diff --git a/mozilla/mailnews/base/src/nsMessenger.cpp b/mozilla/mailnews/base/src/nsMessenger.cpp
index 631e8e17f0a..61368fe4cd2 100644
--- a/mozilla/mailnews/base/src/nsMessenger.cpp
+++ b/mozilla/mailnews/base/src/nsMessenger.cpp
@@ -598,7 +598,7 @@ nsMessenger::SaveAttachment(nsIFileSpec * fileSpec,
     if (NS_FAILED(rv)) goto done;
 
     from.AssignWithConversion(MESSAGE_RFC822);
-    to.AssignWithConversion("text/xul");
+    to.AssignWithConversion("application/vnd.mozilla.xul+xml");
   
     channelSupport = do_QueryInterface(aListener->m_channel);
 
diff --git a/mozilla/mailnews/compose/src/nsMsgQuote.cpp b/mozilla/mailnews/compose/src/nsMsgQuote.cpp
index 831719fb409..5daf6bb6b69 100644
--- a/mozilla/mailnews/compose/src/nsMsgQuote.cpp
+++ b/mozilla/mailnews/compose/src/nsMsgQuote.cpp
@@ -214,7 +214,7 @@ nsMsgQuote::QuoteMessage(const char *msgURI, PRBool quoteHeaders, nsIStreamListe
 
   nsCOMPtr<nsIStreamListener> convertedListener;
   rv = streamConverterService->AsyncConvertData(NS_LITERAL_STRING("message/rfc822").get(),
-                                                NS_LITERAL_STRING("text/xul").get(),
+                                                NS_LITERAL_STRING("application/vnd.mozilla.xul+xml").get(),
                                                 mStreamListener,
                                                 quoteSupport,
                                                 getter_AddRefs(convertedListener));
diff --git a/mozilla/mailnews/mime/build/nsMsgMimeCID.h b/mozilla/mailnews/mime/build/nsMsgMimeCID.h
index 5ed5920e89f..d9464018d9b 100644
--- a/mozilla/mailnews/mime/build/nsMsgMimeCID.h
+++ b/mozilla/mailnews/mime/build/nsMsgMimeCID.h
@@ -27,7 +27,7 @@
   "@mozilla.org/messenger/headerparser;1"
 
 #define NS_MAILNEWS_MIME_STREAM_CONVERTER_CONTRACTID \
-	NS_ISTREAMCONVERTER_KEY "?from=message/rfc822&to=text/xul"
+	NS_ISTREAMCONVERTER_KEY "?from=message/rfc822&to=application/vnd.mozilla.xul+xml"
 
 #define NS_MAILNEWS_MIME_STREAM_CONVERTER_CONTRACTID1 \
 	NS_ISTREAMCONVERTER_KEY "?from=message/rfc822&to=text/html"
diff --git a/mozilla/mailnews/mime/emitters/build/nsMimeEmitterCID.h b/mozilla/mailnews/mime/emitters/build/nsMimeEmitterCID.h
index 24f0b5a032d..335a76081d4 100644
--- a/mozilla/mailnews/mime/emitters/build/nsMimeEmitterCID.h
+++ b/mozilla/mailnews/mime/emitters/build/nsMimeEmitterCID.h
@@ -52,7 +52,7 @@
     { 0xa4, 0x11, 0x0, 0x80, 0x5f, 0x61, 0x3c, 0x79 } }
 
 #define NS_XUL_MIME_EMITTER_CONTRACTID   \
-  NS_MIME_EMITTER_CONTRACTID_PREFIX "text/xul"
+  NS_MIME_EMITTER_CONTRACTID_PREFIX "application/vnd.mozilla.xul+xml"
 // {FAA8AF16-DCFF-11d2-A411-00805F613C19}
 #define NS_XUL_MIME_EMITTER_CID   \
     { 0xfaa8af16, 0xdcff, 0x11d2,         \
diff --git a/mozilla/mailnews/mime/src/nsStreamConverter.cpp b/mozilla/mailnews/mime/src/nsStreamConverter.cpp
index 6a63fedc819..dcb7c34199e 100644
--- a/mozilla/mailnews/mime/src/nsStreamConverter.cpp
+++ b/mozilla/mailnews/mime/src/nsStreamConverter.cpp
@@ -425,13 +425,14 @@ nsStreamConverter::DetermineOutputFormat(const char *url,  nsMimeOutputType *aNe
     {
       // okay, we are just doing a regular message display url
       // since we didn't have any special extensions after the url...
-      // we need to know if we need to use the text/xul or text/html emitter.
+      // we need to know if we need to use the application/vnd.mozilla.xul+xml
+      // or text/html emitter.
       // check the desired output content type that was passed into AsyncConvertData.
 
-      if (mDesiredOutputType && nsCRT::strcasecmp(mDesiredOutputType, "text/xul") == 0)
+      if (mDesiredOutputType && nsCRT::strcasecmp(mDesiredOutputType, "application/vnd.mozilla.xul+xml") == 0)
       {
         CRTFREEIF(mOutputFormat);
-        mOutputFormat = nsCRT::strdup("text/xul");
+        mOutputFormat = nsCRT::strdup("application/vnd.mozilla.xul+xml");
         *aNewType = nsMimeOutput::nsMimeMessageXULDisplay;
       }
       else
@@ -557,7 +558,7 @@ NS_IMETHODIMP nsStreamConverter::Init(nsIURI *aURI, nsIStreamListener * aOutList
   {
     case nsMimeOutput::nsMimeMessageXULDisplay:
       CRTFREEIF(mOutputFormat);
-      mOutputFormat = nsCRT::strdup("text/xul");
+      mOutputFormat = nsCRT::strdup("application/vnd.mozilla.xul+xml");
     break;
 		case nsMimeOutput::nsMimeMessageSplitDisplay:    // the wrapper HTML output to produce the split header/body display
       mWrapperOutput = PR_TRUE;
diff --git a/mozilla/netwerk/mime/public/nsMimeTypes.h b/mozilla/netwerk/mime/public/nsMimeTypes.h
index c6ae9a0ef42..9227a2ac84b 100644
--- a/mozilla/netwerk/mime/public/nsMimeTypes.h
+++ b/mozilla/netwerk/mime/public/nsMimeTypes.h
@@ -112,7 +112,7 @@
 #define TEXT_JSSS                           "text/jsss"
 #define TEXT_XML                            "text/xml"
 #define TEXT_RDF                            "text/rdf"
-#define TEXT_XUL                            "text/xul"
+#define TEXT_XUL                            "application/vnd.mozilla.xul+xml"
 #define TEXT_RTF                            "text/rtf"
 #define TEXT_CPP                            "text/cpp"
 
diff --git a/mozilla/parser/htmlparser/src/nsIParser.h b/mozilla/parser/htmlparser/src/nsIParser.h
index c71720044d9..410987698e1 100644
--- a/mozilla/parser/htmlparser/src/nsIParser.h
+++ b/mozilla/parser/htmlparser/src/nsIParser.h
@@ -354,7 +354,7 @@ const PRUnichar kNullCh           = '\0';
 
 #define kHTMLTextContentType  "text/html"
 #define kXMLTextContentType   "text/xml"
-#define kXULTextContentType   "text/xul"
+#define kXULTextContentType   "application/vnd.mozilla.xul+xml"
 #define kRDFTextContentType   "text/rdf"
 #define kXIFTextContentType   "text/xif"
 #define kPlainTextContentType "text/plain"
diff --git a/mozilla/rdf/chrome/src/nsChromeProtocolHandler.cpp b/mozilla/rdf/chrome/src/nsChromeProtocolHandler.cpp
index 7495c80389f..36ee9e0f481 100644
--- a/mozilla/rdf/chrome/src/nsChromeProtocolHandler.cpp
+++ b/mozilla/rdf/chrome/src/nsChromeProtocolHandler.cpp
@@ -327,7 +327,7 @@ nsCachedChromeChannel::SetNotificationCallbacks(nsIInterfaceRequestor * aNotific
 NS_IMETHODIMP 
 nsCachedChromeChannel::GetContentType(char * *aContentType)
 {
-    *aContentType = nsXPIDLCString::Copy("text/cached-xul");
+    *aContentType = nsXPIDLCString::Copy("mozilla.application/cached-xul");
     return *aContentType ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
 }
 
diff --git a/mozilla/xpfe/browser/src/nsBrowserInstance.cpp b/mozilla/xpfe/browser/src/nsBrowserInstance.cpp
index 37aff5ce97f..1e1787f154e 100644
--- a/mozilla/xpfe/browser/src/nsBrowserInstance.cpp
+++ b/mozilla/xpfe/browser/src/nsBrowserInstance.cpp
@@ -1088,7 +1088,7 @@ nsBrowserInstance::IsPreferred(const char * aContentType,
   // regardlesss of the uri load command.
   //    incoming Type                     Preferred type
   //      text/html
-  //      text/xul
+  //      application/vnd.mozilla.xul+xml
   //      text/rdf
   //      text/xml
   //      text/css
@@ -1103,7 +1103,7 @@ nsBrowserInstance::IsPreferred(const char * aContentType,
      // (1) list all content types we want to  be the primary handler for....
      // and suggest a desired content type if appropriate...
      if (nsCRT::strcasecmp(aContentType,  "text/html") == 0
-       || nsCRT::strcasecmp(aContentType, "text/xul") == 0
+       || nsCRT::strcasecmp(aContentType, "application/vnd.mozilla.xul+xml") == 0
        || nsCRT::strcasecmp(aContentType, "text/rdf") == 0 
        || nsCRT::strcasecmp(aContentType, "text/xml") == 0
        || nsCRT::strcasecmp(aContentType, "text/css") == 0
@@ -1551,7 +1551,7 @@ static nsModuleComponentInfo components[] = {
   },
   { "Browser Content Handler",
     NS_BROWSERCONTENTHANDLER_CID,
-    NS_CONTENT_HANDLER_CONTRACTID_PREFIX"text/xul", 
+    NS_CONTENT_HANDLER_CONTRACTID_PREFIX"application/vnd.mozilla.xul+xml", 
     nsBrowserContentHandlerConstructor 
   },
   { "Browser Content Handler",
diff --git a/mozilla/xpfe/components/directory/nsDirectoryViewer.cpp b/mozilla/xpfe/components/directory/nsDirectoryViewer.cpp
index 03fd2b6701a..a6e1db9846f 100644
--- a/mozilla/xpfe/components/directory/nsDirectoryViewer.cpp
+++ b/mozilla/xpfe/components/directory/nsDirectoryViewer.cpp
@@ -1778,7 +1778,7 @@ nsDirectoryViewerFactory::CreateInstance(const char *aCommand,
 
   // Create a dummy loader that will load a stub XUL document.
   nsCOMPtr<nsIDocumentLoaderFactory> factory;
-  rv = nsComponentManager::CreateInstance(NS_DOCUMENT_LOADER_FACTORY_CONTRACTID_PREFIX "view;1?type=text/xul",
+  rv = nsComponentManager::CreateInstance(NS_DOCUMENT_LOADER_FACTORY_CONTRACTID_PREFIX "view;1?type=application/vnd.mozilla.xul+xml",
                                           nsnull,
                                           NS_GET_IID(nsIDocumentLoaderFactory),
                                           getter_AddRefs(factory));
@@ -1793,7 +1793,7 @@ nsDirectoryViewerFactory::CreateInstance(const char *aCommand,
   if (NS_FAILED(rv)) return rv;
 
   nsCOMPtr<nsIStreamListener> listener;
-  rv = factory->CreateInstance("view", channel, aLoadGroup, "text/xul",
+  rv = factory->CreateInstance("view", channel, aLoadGroup, "application/vnd.mozilla.xul+xml",
                                aContainer, aExtraInfo, getter_AddRefs(listener),
                                aDocViewerResult);
   if (NS_FAILED(rv)) return rv;