diff --git a/libraries/idl/org.khronos.webgl.idl b/libraries/idl/org.khronos.webgl.idl
index 6d607e6bc4c..7e029965020 100644
--- a/libraries/idl/org.khronos.webgl.idl
+++ b/libraries/idl/org.khronos.webgl.idl
@@ -1,6 +1,7 @@
 namespace org.khronos.webgl;
 
 
+// Downloaded from https://www.khronos.org/registry/webgl/specs/latest/1.0/webgl.idl
 // AUTOGENERATED FILE -- DO NOT EDIT -- SEE Makefile
 //
 // WebGL IDL definitions scraped from the Khronos specification:
@@ -741,6 +742,7 @@ dictionary WebGLContextEventInit : EventInit {
     DOMString statusMessage;
 };
 
+// Downloaded from https://www.khronos.org/registry/typedarray/specs/latest/typedarray.idl
 /*
  * typedarray.idl
  *
diff --git a/libraries/idl/org.w3c.dom.css.idl b/libraries/idl/org.w3c.dom.css.idl
index 904df1e7ee7..d701488b6ce 100644
--- a/libraries/idl/org.w3c.dom.css.idl
+++ b/libraries/idl/org.w3c.dom.css.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.dom.css;
 
 
+// Downloaded from http://dev.w3.org/csswg/cssom/
 [ArrayClass]interface MediaList {
   [TreatNullAs=EmptyString] stringifier attribute DOMString mediaText;
   readonly attribute unsigned long length;
diff --git a/libraries/idl/org.w3c.dom.events.idl b/libraries/idl/org.w3c.dom.events.idl
index c24ce4f46e3..7464fb50e33 100644
--- a/libraries/idl/org.w3c.dom.events.idl
+++ b/libraries/idl/org.w3c.dom.events.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.dom.events;
 
 
+// Downloaded from http://www.w3.org/TR/uievents/
 [Constructor(DOMString type, optional UIEventInit eventInitDict)]
 interface UIEvent : Event {
  readonly attribute Window? view;
diff --git a/libraries/idl/org.w3c.dom.idl b/libraries/idl/org.w3c.dom.idl
index 2e884354a62..0fffd391766 100644
--- a/libraries/idl/org.w3c.dom.idl
+++ b/libraries/idl/org.w3c.dom.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.dom;
 
 
+// Downloaded from https://raw.githubusercontent.com/whatwg/html-mirror/master/source
 typedef (Int8Array or Uint8Array or Uint8ClampedArray or
          Int16Array or Uint16Array or
          Int32Array or Uint32Array or
@@ -2018,6 +2019,7 @@ partial interface Window {
   void captureEvents();
   void releaseEvents();
 };
+// Downloaded from https://html.spec.whatwg.org/
 typedef (Int8Array or Uint8Array or Uint8ClampedArray or
          Int16Array or Uint16Array or
          Int32Array or Uint32Array or
@@ -4129,6 +4131,7 @@ partial interface Window {
   void captureEvents();
   void releaseEvents();
 };
+// Downloaded from https://raw.githubusercontent.com/whatwg/dom/master/dom.html
 [Constructor(DOMString type, optional EventInit eventInitDict),
  Exposed=(Window,Worker)]
 interface Event {
@@ -5049,6 +5052,7 @@ interface DOMTokenList {
 interface DOMSettableTokenList : DOMTokenList {
             attribute DOMString value;
 };
+// Downloaded from https://dvcs.w3.org/hg/editing/raw-file/tip/editing.html
 interface Selection {
   readonly attribute Node? anchorNode;
   readonly attribute unsigned long anchorOffset;
@@ -5100,6 +5104,7 @@ dictionary EditingInputEventInit : EventInit {
   DOMString command;
   DOMString value;
 };
+// Downloaded from http://www.w3.org/TR/animation-timing/
 partial interface Window {
   long requestAnimationFrame(FrameRequestCallback callback);
   void cancelAnimationFrame(long handle);
diff --git a/libraries/idl/org.w3c.dom.parsing.idl b/libraries/idl/org.w3c.dom.parsing.idl
index 3b956ba278d..4b6f53be4c2 100644
--- a/libraries/idl/org.w3c.dom.parsing.idl
+++ b/libraries/idl/org.w3c.dom.parsing.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.dom.parsing;
 
 
+// Downloaded from http://www.w3.org/TR/DOM-Parsing/
 [Constructor]
 interface DOMParser {
  [NewObject] Document parseFromString (DOMString str, SupportedType type);
diff --git a/libraries/idl/org.w3c.dom.svg.idl b/libraries/idl/org.w3c.dom.svg.idl
index 9331b8164e8..536a8700a0c 100644
--- a/libraries/idl/org.w3c.dom.svg.idl
+++ b/libraries/idl/org.w3c.dom.svg.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.dom.svg;
 
 
+// Downloaded from http://web.archive.org/web/20150317051602/http://www.w3.org/TR/SVG11/single-page.html
 interface SVGDocument : Document,
                         DocumentEvent {
   readonly attribute DOMString title;
diff --git a/libraries/idl/org.w3c.fetch.idl b/libraries/idl/org.w3c.fetch.idl
index 1bc46149cc2..c89b6de5bb1 100644
--- a/libraries/idl/org.w3c.fetch.idl
+++ b/libraries/idl/org.w3c.fetch.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.fetch;
 
 
+// Downloaded from https://raw.githubusercontent.com/whatwg/fetch/master/Overview.src.html
 typedef (Headers or sequence<sequence<ByteString>> or OpenEndedDictionary<ByteString>) HeadersInit;
 [Constructor(optional HeadersInit init),
  Exposed=(Window,Worker)]
diff --git a/libraries/idl/org.w3c.files.idl b/libraries/idl/org.w3c.files.idl
index cc8f49dda37..b3f51de2724 100644
--- a/libraries/idl/org.w3c.files.idl
+++ b/libraries/idl/org.w3c.files.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.files;
 
 
+// Downloaded from https://raw.githubusercontent.com/w3c/FileAPI/gh-pages/index.html
 [Constructor, Constructor(sequence<(ArrayBuffer or ArrayBufferView or Blob or DOMString)> blobParts, optional BlobPropertyBag options), Exposed=Window,Worker] interface Blob {
       
       readonly attribute unsigned long long size;
diff --git a/libraries/idl/org.w3c.fullscreen.idl b/libraries/idl/org.w3c.fullscreen.idl
index 068449e2c56..9d2d4585c8c 100644
--- a/libraries/idl/org.w3c.fullscreen.idl
+++ b/libraries/idl/org.w3c.fullscreen.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.fullscreen;
 
 
+// Downloaded from https://raw.githubusercontent.com/whatwg/fullscreen/master/Overview.src.html
 partial interface Element {
   void requestFullscreen();
 };
diff --git a/libraries/idl/org.w3c.notifications.idl b/libraries/idl/org.w3c.notifications.idl
index d35f588d5d5..c3c7594bfb5 100644
--- a/libraries/idl/org.w3c.notifications.idl
+++ b/libraries/idl/org.w3c.notifications.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.notifications;
 
 
+// Downloaded from https://raw.githubusercontent.com/whatwg/notifications/master/notifications.html
 [Constructor(DOMString title, optional NotificationOptions options),
  Exposed=(Window,Worker)]
 interface Notification : EventTarget {
diff --git a/libraries/idl/org.w3c.performance.idl b/libraries/idl/org.w3c.performance.idl
index 7d59736168e..6447bea5e43 100644
--- a/libraries/idl/org.w3c.performance.idl
+++ b/libraries/idl/org.w3c.performance.idl
@@ -1,10 +1,12 @@
 namespace org.w3c.performance;
 
 
+// Downloaded from http://www.w3.org/TR/hr-time/
 typedef double DOMHighResTimeStamp;
 partial interface Performance {
   DOMHighResTimeStamp now();
 };
+// Downloaded from http://www.w3.org/TR/2012/REC-navigation-timing-20121217/
 interface PerformanceTiming {
   readonly attribute unsigned long long navigationStart;
   readonly attribute unsigned long long unloadEventStart;
diff --git a/libraries/idl/org.w3c.vibration.idl b/libraries/idl/org.w3c.vibration.idl
index bb47739f37f..96372dd71e5 100644
--- a/libraries/idl/org.w3c.vibration.idl
+++ b/libraries/idl/org.w3c.vibration.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.vibration;
 
 
+// Downloaded from http://www.w3.org/TR/vibration/
 typedef (unsigned long or sequence<unsigned long>) VibratePattern; partial interface Navigator {
  boolean vibrate (VibratePattern pattern);
 };
diff --git a/libraries/idl/org.w3c.workers.idl b/libraries/idl/org.w3c.workers.idl
index 8e4625ffcda..17a958be5fa 100644
--- a/libraries/idl/org.w3c.workers.idl
+++ b/libraries/idl/org.w3c.workers.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.workers;
 
 
+// Downloaded from http://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html
 [Exposed=(Window,Worker)]
 interface ServiceWorker : EventTarget {
   readonly attribute USVString scriptURL;
@@ -22,34 +23,34 @@ enum ServiceWorkerState {
 };
 [Exposed=(Window,Worker)]
 interface ServiceWorkerRegistration : EventTarget {
-  [Unforgeable] readonly attribute ServiceWorker? installing;
-  [Unforgeable] readonly attribute ServiceWorker? waiting;
-  [Unforgeable] readonly attribute ServiceWorker? active;
+  [Unforgeable, SameObject] readonly attribute ServiceWorker? installing;
+  [Unforgeable, SameObject] readonly attribute ServiceWorker? waiting;
+  [Unforgeable, SameObject] readonly attribute ServiceWorker? active;
 
   readonly attribute USVString scope;
 
   void update();
-  Promise<boolean> unregister();
+  [NewObject] Promise<boolean> unregister();
 
   // event
   attribute EventHandler onupdatefound;
 };
 partial interface Navigator {
-  readonly attribute ServiceWorkerContainer serviceWorker;
+  [SameObject] readonly attribute ServiceWorkerContainer serviceWorker;
 };
 
 partial interface WorkerNavigator {
-  readonly attribute ServiceWorkerContainer serviceWorker;
+  [SameObject] readonly attribute ServiceWorkerContainer serviceWorker;
 };
 [Exposed=(Window,Worker)]
 interface ServiceWorkerContainer : EventTarget {
-  [Unforgeable] readonly attribute ServiceWorker? controller;
-  readonly attribute Promise<ServiceWorkerRegistration> ready;
+  [Unforgeable, SameObject] readonly attribute ServiceWorker? controller;
+  [SameObject] readonly attribute Promise<ServiceWorkerRegistration> ready;
 
-  Promise<ServiceWorkerRegistration> register(USVString scriptURL, optional RegistrationOptions options);
+  [NewObject] Promise<ServiceWorkerRegistration> register(USVString scriptURL, optional RegistrationOptions options);
 
-  Promise<ServiceWorkerRegistration> getRegistration(optional USVString clientURL = "");
-  Promise<sequence<ServiceWorkerRegistration>?> getRegistrations();
+  [NewObject] Promise<ServiceWorkerRegistration> getRegistration(optional USVString clientURL = "");
+  [NewObject] Promise<sequence<ServiceWorkerRegistration>?> getRegistrations();
 
 
   // events
@@ -66,8 +67,8 @@ interface ServiceWorkerMessageEvent : Event {
   readonly attribute any data;
   readonly attribute DOMString origin;
   readonly attribute DOMString lastEventId;
-  readonly attribute (ServiceWorker or MessagePort)? source;
-  readonly attribute MessagePort[]? ports;
+  [SameObject] readonly attribute (ServiceWorker or MessagePort)? source;
+  [SameObject] readonly attribute MessagePort[]? ports;
 
   void initServiceWorkerMessageEvent(DOMString typeArg, boolean canBubbleArg, boolean cancelableArg, any dataArg, DOMString originArg, DOMString lastEventIdArg, (ServiceWorker or MessagePort) sourceArg, sequence<MessagePort>? portsArg);
 };
@@ -83,10 +84,10 @@ dictionary ServiceWorkerMessageEventInit : EventInit {
 interface ServiceWorkerGlobalScope : WorkerGlobalScope {
   // A container for a list of Client objects that correspond to
   // browsing contexts (or shared workers) that are on the origin of this SW
-  readonly attribute Clients clients;
-  readonly attribute ServiceWorkerRegistration registration;
+  [SameObject] readonly attribute Clients clients;
+  [SameObject] readonly attribute ServiceWorkerRegistration registration;
 
-  Promise<void> skipWaiting();
+  [NewObject] Promise<void> skipWaiting();
 
   attribute EventHandler oninstall;
   attribute EventHandler onactivate;
@@ -109,7 +110,7 @@ interface Client {
 interface WindowClient : Client {
   readonly attribute VisibilityState visibilityState;
   readonly attribute boolean focused;
-  Promise<WindowClient> focus();
+  [NewObject] Promise<WindowClient> focus();
 };
 
 enum FrameType {
@@ -121,9 +122,9 @@ enum FrameType {
 [Exposed=ServiceWorker]
 interface Clients {
   // The objects returned will be new instances every time
-  Promise<sequence<Client>?> matchAll(optional ClientQueryOptions options);
-  Promise<WindowClient> openWindow(USVString url);
-  Promise<void> claim();
+  [NewObject] Promise<sequence<Client>?> matchAll(optional ClientQueryOptions options);
+  [NewObject] Promise<WindowClient> openWindow(USVString url);
+  [NewObject] Promise<void> claim();
 };
 
 dictionary ClientQueryOptions {
@@ -147,8 +148,8 @@ dictionary ExtendableEventInit : EventInit {
 };
 [Constructor(DOMString type, optional FetchEventInit eventInitDict), Exposed=ServiceWorker]
 interface FetchEvent : ExtendableEvent {
-  readonly attribute Request request;
-  readonly attribute Client client;
+  [SameObject] readonly attribute Request request;
+  [SameObject] readonly attribute Client client;
   readonly attribute boolean isReload;
 
   void respondWith((Response or Promise<Response>) r);
@@ -164,8 +165,8 @@ interface ExtendableMessageEvent : ExtendableEvent {
   readonly attribute any data;
   readonly attribute DOMString origin;
   readonly attribute DOMString lastEventId;
-  readonly attribute (Client or ServiceWorker or MessagePort)? source;
-  readonly attribute MessagePort[]? ports;
+  [SameObject] readonly attribute (Client or ServiceWorker or MessagePort)? source;
+  [SameObject] readonly attribute MessagePort[]? ports;
 
   void initExtendableMessageEvent(DOMString typeArg, boolean canBubbleArg, boolean cancelableArg, any dataArg, DOMString originArg, DOMString lastEventIdArg, (Client or ServiceWorker or MessagePort) sourceArg, sequence<MessagePort>? portsArg);
 };
@@ -178,21 +179,21 @@ dictionary ExtendableMessageEventInit : ExtendableEventInit {
   sequence<MessagePort> ports;
 };
 partial interface Window {
-  readonly attribute CacheStorage caches;
+  [SameObject] readonly attribute CacheStorage caches;
 };
 
 partial interface WorkerGlobalScope {
-  readonly attribute CacheStorage caches;
+  [SameObject] readonly attribute CacheStorage caches;
 };
 [Exposed=(Window,Worker)]
 interface Cache {
-  Promise<Response> match(RequestInfo request, optional CacheQueryOptions options);
-  Promise<sequence<Response>> matchAll(optional RequestInfo request, optional CacheQueryOptions options);
-  Promise<void> add(RequestInfo request);
-  Promise<void> addAll(sequence<RequestInfo> requests);
-  Promise<void> put(RequestInfo request, Response response);
-  Promise<boolean> delete(RequestInfo request, optional CacheQueryOptions options);
-  Promise<sequence<Request>> keys(optional RequestInfo request, optional CacheQueryOptions options);
+  [NewObject] Promise<Response> match(RequestInfo request, optional CacheQueryOptions options);
+  [NewObject] Promise<sequence<Response>> matchAll(optional RequestInfo request, optional CacheQueryOptions options);
+  [NewObject] Promise<void> add(RequestInfo request);
+  [NewObject] Promise<void> addAll(sequence<RequestInfo> requests);
+  [NewObject] Promise<void> put(RequestInfo request, Response response);
+  [NewObject] Promise<boolean> delete(RequestInfo request, optional CacheQueryOptions options);
+  [NewObject] Promise<sequence<Request>> keys(optional RequestInfo request, optional CacheQueryOptions options);
 };
 
 dictionary CacheQueryOptions {
@@ -210,11 +211,11 @@ dictionary CacheBatchOperation {
 };
 [Exposed=(Window,Worker)]
 interface CacheStorage {
-  Promise<Response> match(RequestInfo request, optional CacheQueryOptions options);
-  Promise<boolean> has(DOMString cacheName);
-  Promise<Cache> open(DOMString cacheName);
-  Promise<boolean> delete(DOMString cacheName);
-  Promise<sequence<DOMString>> keys();
+  [NewObject] Promise<Response> match(RequestInfo request, optional CacheQueryOptions options);
+  [NewObject] Promise<boolean> has(DOMString cacheName);
+  [NewObject] Promise<Cache> open(DOMString cacheName);
+  [NewObject] Promise<boolean> delete(DOMString cacheName);
+  [NewObject] Promise<sequence<DOMString>> keys();
 };
 partial interface ServiceWorkerRegistration {
   // e.g. define an API namespace
diff --git a/libraries/idl/org.w3c.xhr.idl b/libraries/idl/org.w3c.xhr.idl
index cd6af9e97e1..0a6c77aaac5 100644
--- a/libraries/idl/org.w3c.xhr.idl
+++ b/libraries/idl/org.w3c.xhr.idl
@@ -1,6 +1,7 @@
 namespace org.w3c.xhr;
 
 
+// Downloaded from https://raw.githubusercontent.com/whatwg/xhr/master/Overview.src.html
 [Exposed=(Window,Worker)]
 interface XMLHttpRequestEventTarget : EventTarget {
   // event handlers
diff --git a/libraries/tools/idl2k/src/main/kotlin/download.kt b/libraries/tools/idl2k/src/main/kotlin/download.kt
index e402b01bd2d..dcc338a60b9 100644
--- a/libraries/tools/idl2k/src/main/kotlin/download.kt
+++ b/libraries/tools/idl2k/src/main/kotlin/download.kt
@@ -69,6 +69,7 @@ fun main(args: Array<String>) {
                 val (url) = pair
                 println("Loading ${url}...")
 
+                w.appendln("// Downloaded from $url")
                 if (url.endsWith(".idl")) {
                     w.appendln(URL(url).readText())
                 } else {