--- a/gfx/layers/LayersLogging.cpp
+++ b/gfx/layers/LayersLogging.cpp
@@ -224,17 +224,17 @@ AppendToString(std::stringstream& aStrea
   aStream << sfx;
 }
 
 void
 AppendToString(std::stringstream& aStream, const ScrollableLayerGuid& s,
                const char* pfx, const char* sfx)
 {
   aStream << pfx
-          << nsPrintfCString("{ l=%" PRIu64 ", p=%u, v=%" PRIu64 " }", s.mLayersId, s.mPresShellId, s.mScrollId).get()
+          << nsPrintfCString("{ l=0x%" PRIx64 ", p=%u, v=%" PRIu64 " }", s.mLayersId, s.mPresShellId, s.mScrollId).get()
           << sfx;
 }
 
 void
 AppendToString(std::stringstream& aStream, const ZoomConstraints& z,
                const char* pfx, const char* sfx)
 {
   aStream << pfx

--- a/gfx/layers/apz/src/APZCTreeManager.cpp
+++ b/gfx/layers/apz/src/APZCTreeManager.cpp
@@ -968,17 +968,17 @@ WillHandleInput(const PanGestureOrScroll
 }
 
 void
 APZCTreeManager::FlushApzRepaints(uint64_t aLayersId)
 {
   // Previously, paints were throttled and therefore this method was used to
   // ensure any pending paints were flushed. Now, paints are flushed
   // immediately, so it is safe to simply send a notification now.
-  APZCTM_LOG("Flushing repaints for layers id %" PRIu64, aLayersId);
+  APZCTM_LOG("Flushing repaints for layers id 0x%" PRIx64, aLayersId);
   const LayerTreeState* state =
     CompositorBridgeParent::GetIndirectShadowTree(aLayersId);
   MOZ_ASSERT(state && state->mController);
   state->mController->DispatchToRepaintThread(
     NewRunnableMethod("layers::GeckoContentController::NotifyFlushComplete",
                       state->mController,
                       &GeckoContentController::NotifyFlushComplete));
 }

--- a/gfx/layers/apz/src/HitTestingTreeNode.cpp
+++ b/gfx/layers/apz/src/HitTestingTreeNode.cpp
@@ -335,17 +335,17 @@ HitTestingTreeNode::GetVisibleRegion() c
 void
 HitTestingTreeNode::Dump(const char* aPrefix) const
 {
   if (mPrevSibling) {
     mPrevSibling->Dump(aPrefix);
   }
   printf_stderr("%sHitTestingTreeNode (%p) APZC (%p) g=(%s) %s%s%sr=(%s) t=(%s) c=(%s)%s%s\n",
     aPrefix, this, mApzc.get(),
-    mApzc ? Stringify(mApzc->GetGuid()).c_str() : nsPrintfCString("l=%" PRIu64, mLayersId).get(),
+    mApzc ? Stringify(mApzc->GetGuid()).c_str() : nsPrintfCString("l=0x%" PRIx64, mLayersId).get(),
     (mOverride & EventRegionsOverride::ForceDispatchToContent) ? "fdtc " : "",
     (mOverride & EventRegionsOverride::ForceEmptyHitRegion) ? "fehr " : "",
     (mFixedPosTarget != FrameMetrics::NULL_SCROLL_ID) ? nsPrintfCString("fixed=%" PRIu64 " ", mFixedPosTarget).get() : "",
     Stringify(mEventRegions).c_str(), Stringify(mTransform).c_str(),
     mClipRegion ? Stringify(mClipRegion.ref()).c_str() : "none",
     mIsScrollbarContainer ? " scrollbar" : "",
     IsScrollThumbNode() ? " scrollthumb" : "");
   if (mLastChild) {

--- a/gfx/layers/wr/WebRenderScrollData.cpp
+++ b/gfx/layers/wr/WebRenderScrollData.cpp
@@ -109,17 +109,17 @@ WebRenderLayerScrollData::Dump(const Web
   for (size_t i : mScrollIds) {
     printf_stderr("  metadata: %s\n", Stringify(aOwner.GetScrollMetadata(i)).c_str());
   }
   printf_stderr("  transform: %s perspective: %d visible: %s\n",
     Stringify(mTransform).c_str(), mTransformIsPerspective,
     Stringify(mVisibleRegion).c_str());
   printf_stderr("  event regions: %s override: 0x%x\n",
     Stringify(mEventRegions).c_str(), mEventRegionsOverride);
-  printf_stderr("  ref layers id: %" PRIu64 "\n", mReferentId.valueOr(0));
+  printf_stderr("  ref layers id: 0x%" PRIx64 "\n", mReferentId.valueOr(0));
   //printf_stderr("  scroll thumb: %s animation: %" PRIu64 "\n",
   //  Stringify(mScrollThumbData).c_str(), mScrollbarAnimationId);
   printf_stderr("  scroll container: %d target: %" PRIu64 "\n",
     mIsScrollbarContainer, mScrollbarTargetContainerId);
   printf_stderr("  fixed pos container: %" PRIu64 "\n",
     mFixedPosScrollContainerId);
 }