diff --git a/layout/base/nsRefreshDriver.cpp b/layout/base/nsRefreshDriver.cpp
index 998bd876806c..f642ad539dc1 100644
--- a/layout/base/nsRefreshDriver.cpp
+++ b/layout/base/nsRefreshDriver.cpp
@@ -75,7 +75,6 @@
 #include "mozilla/layout/VsyncChild.h"
 #include "VsyncSource.h"
 #include "mozilla/VsyncDispatcher.h"
-#include "nsThreadUtils.h"
 #include "mozilla/Unused.h"
 #include "mozilla/TimelineConsumers.h"
 #include "nsAnimationManager.h"
@@ -2107,6 +2106,9 @@ void nsRefreshDriver::Tick(VsyncId aId, TimeStamp aNowTime) {
           if (!mStyleFlushObservers.RemoveElement(rawPresShell)) {
             continue;
           }
+
+          LogPresShellObserver::Run run(rawPresShell, this);
+
           RefPtr<PresShell> presShell = rawPresShell;
           presShell->mObservingStyleFlushes = false;
           presShell->FlushPendingNotifications(
@@ -2133,6 +2135,9 @@ void nsRefreshDriver::Tick(VsyncId aId, TimeStamp aNowTime) {
         if (!mLayoutFlushObservers.RemoveElement(rawPresShell)) {
           continue;
         }
+
+        LogPresShellObserver::Run run(rawPresShell, this);
+
         RefPtr<PresShell> presShell = rawPresShell;
         presShell->mObservingLayoutFlushes = false;
         presShell->mWasLastReflowInterrupted = false;
diff --git a/layout/base/nsRefreshDriver.h b/layout/base/nsRefreshDriver.h
index 09d3bf32c97e..86d7893bd0b0 100644
--- a/layout/base/nsRefreshDriver.h
+++ b/layout/base/nsRefreshDriver.h
@@ -23,6 +23,7 @@
 #include "nsClassHashtable.h"
 #include "nsHashKeys.h"
 #include "nsRefreshObservers.h"
+#include "nsThreadUtils.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/dom/VisualViewport.h"
@@ -54,6 +55,7 @@ class nsRefreshDriver final : public mozilla::layers::TransactionIdAllocator,
       mozilla::dom::VisualViewport::VisualViewportResizeEvent;
   using VVPScrollEvent =
       mozilla::dom::VisualViewport::VisualViewportScrollEvent;
+  using LogPresShellObserver = mozilla::LogPresShellObserver;
 
  public:
   explicit nsRefreshDriver(nsPresContext* aPresContext);
@@ -170,6 +172,7 @@ class nsRefreshDriver final : public mozilla::layers::TransactionIdAllocator,
   void AddStyleFlushObserver(mozilla::PresShell* aPresShell) {
     MOZ_DIAGNOSTIC_ASSERT(!mStyleFlushObservers.Contains(aPresShell),
                           "Double-adding style flush observer");
+    LogPresShellObserver::LogDispatch(aPresShell, this);
     mStyleFlushObservers.AppendElement(aPresShell);
     EnsureTimerStarted();
   }
@@ -180,6 +183,7 @@ class nsRefreshDriver final : public mozilla::layers::TransactionIdAllocator,
   void AddLayoutFlushObserver(mozilla::PresShell* aPresShell) {
     MOZ_DIAGNOSTIC_ASSERT(!IsLayoutFlushObserver(aPresShell),
                           "Double-adding layout flush observer");
+    LogPresShellObserver::LogDispatch(aPresShell, this);
     mLayoutFlushObservers.AppendElement(aPresShell);
     EnsureTimerStarted();
   }
diff --git a/xpcom/threads/nsThreadUtils.cpp b/xpcom/threads/nsThreadUtils.cpp
index 25eaf21312a3..b17bc6c3a1e4 100644
--- a/xpcom/threads/nsThreadUtils.cpp
+++ b/xpcom/threads/nsThreadUtils.cpp
@@ -629,6 +629,10 @@ template <typename T>
 void LogTaskBase<T>::LogDispatch(T* aEvent) {
   LOG1(("DISP %p", aEvent));
 }
+template <typename T>
+void LogTaskBase<T>::LogDispatch(T* aEvent, void* aContext) {
+  LOG1(("DISP %p (%p)", aEvent, aContext));
+}
 
 template <>
 void LogTaskBase<IPC::Message>::LogDispatchWithPid(IPC::Message* aEvent,
@@ -646,6 +650,11 @@ LogTaskBase<T>::Run::Run(T* aEvent, bool aWillRunAgain)
   // time.
   LOG1(("EXEC %p %p", aEvent, this));
 }
+template <typename T>
+LogTaskBase<T>::Run::Run(T* aEvent, void* aContext, bool aWillRunAgain)
+    : mWillRunAgain(aWillRunAgain) {
+  LOG1(("EXEC %p (%p) %p", aEvent, aContext, this));
+}
 
 template <>
 LogTaskBase<nsIRunnable>::Run::Run(nsIRunnable* aEvent, bool aWillRunAgain)
@@ -690,6 +699,7 @@ template class LogTaskBase<MicroTaskRunnable>;
 template class LogTaskBase<IPC::Message>;
 template class LogTaskBase<nsTimerImpl>;
 template class LogTaskBase<Task>;
+template class LogTaskBase<PresShell>;
 
 MOZ_THREAD_LOCAL(nsISerialEventTarget*)
 SerialEventTargetGuard::sCurrentThreadTLS;
diff --git a/xpcom/threads/nsThreadUtils.h b/xpcom/threads/nsThreadUtils.h
index 361c02bcb69a..e3e9381b9d20 100644
--- a/xpcom/threads/nsThreadUtils.h
+++ b/xpcom/threads/nsThreadUtils.h
@@ -1923,6 +1923,8 @@ class LogTaskBase {
 
   // Adds a simple log about dispatch of this runnable.
   static void LogDispatch(T* aEvent);
+  // The `aContext` pointer adds another uniqe identifier, nothing more
+  static void LogDispatch(T* aEvent, void* aContext);
 
   // Logs dispatch of the message and along that also the PID of the target
   // proccess, purposed for uniquely identifying IPC messages.
@@ -1936,6 +1938,7 @@ class LogTaskBase {
    public:
     Run() = delete;
     explicit Run(T* aEvent, bool aWillRunAgain = false);
+    explicit Run(T* aEvent, void* aContext, bool aWillRunAgain = false);
     ~Run();
 
     // When this is called, the log in this RAII dtor will only say
@@ -1949,6 +1952,7 @@ class LogTaskBase {
 
 class MicroTaskRunnable;
 class Task;  // TaskController
+class PresShell;
 
 // Specialized methods must be explicitly predeclared.
 template <>
@@ -1966,6 +1970,7 @@ typedef LogTaskBase<MicroTaskRunnable> LogMicroTaskRunnable;
 typedef LogTaskBase<IPC::Message> LogIPCMessage;
 typedef LogTaskBase<nsTimerImpl> LogTimerEvent;
 typedef LogTaskBase<Task> LogTask;
+typedef LogTaskBase<PresShell> LogPresShellObserver;
 // If you add new types don't forget to add:
 // `template class LogTaskBase<YourType>;` to nsThreadUtils.cpp