diff --git a/dom/localstorage/ActorsParent.cpp b/dom/localstorage/ActorsParent.cpp
index bd4eabd07bc3..3f0450a6884a 100644
--- a/dom/localstorage/ActorsParent.cpp
+++ b/dom/localstorage/ActorsParent.cpp
@@ -1593,7 +1593,7 @@ class Datastore final
 
   void Clear(Database* aDatabase);
 
-  void BeginUpdateBatch(int64_t aSnapshotInitialUsage);
+  void BeginUpdateBatch(int64_t aSnapshotUsage);
 
   int64_t EndUpdateBatch(int64_t aSnapshotPeakUsage);
 
@@ -1956,12 +1956,12 @@ class Snapshot final : public PBackgroundLSSnapshotParent {
 
   void Init(nsTHashtable<nsStringHashKey>& aLoadedItems,
             nsTHashSet<nsString>&& aUnknownItems, uint32_t aNextLoadIndex,
-            uint32_t aTotalLength, int64_t aInitialUsage, int64_t aPeakUsage,
+            uint32_t aTotalLength, int64_t aUsage, int64_t aPeakUsage,
             LSSnapshot::LoadState aLoadState, bool aHasOtherProcessDatabases,
             bool aHasOtherProcessObservers) {
     AssertIsOnBackgroundThread();
-    MOZ_ASSERT(aInitialUsage >= 0);
-    MOZ_ASSERT(aPeakUsage >= aInitialUsage);
+    MOZ_ASSERT(aUsage >= 0);
+    MOZ_ASSERT(aPeakUsage >= aUsage);
     MOZ_ASSERT_IF(aLoadState != LSSnapshot::LoadState::AllOrderedItems,
                   aNextLoadIndex < aTotalLength);
     MOZ_ASSERT(mTotalLength == 0);
@@ -1972,7 +1972,7 @@ class Snapshot final : public PBackgroundLSSnapshotParent {
     mUnknownItems = std::move(aUnknownItems);
     mNextLoadIndex = aNextLoadIndex;
     mTotalLength = aTotalLength;
-    mUsage = aInitialUsage;
+    mUsage = aUsage;
     mPeakUsage = aPeakUsage;
     if (aLoadState == LSSnapshot::LoadState::AllOrderedKeys) {
       MOZ_ASSERT(mUnknownItems.Count() == 0);
@@ -4963,15 +4963,15 @@ void Datastore::Clear(Database* aDatabase) {
   }
 }
 
-void Datastore::BeginUpdateBatch(int64_t aSnapshotInitialUsage) {
+void Datastore::BeginUpdateBatch(int64_t aSnapshotUsage) {
   AssertIsOnBackgroundThread();
-  // Don't assert `aSnapshotInitialUsage >= 0`, it can be negative when multiple
+  // Don't assert `aSnapshotUsage >= 0`, it can be negative when multiple
   // snapshots are operating in parallel.
   MOZ_ASSERT(!mClosed);
   MOZ_ASSERT(mUpdateBatchUsage == -1);
   MOZ_ASSERT(!mInUpdateBatch);
 
-  mUpdateBatchUsage = aSnapshotInitialUsage;
+  mUpdateBatchUsage = aSnapshotUsage;
 
   if (IsPersistent()) {
     mConnection->BeginUpdateBatch();
@@ -5560,9 +5560,9 @@ mozilla::ipc::IPCResult Database::RecvPBackgroundLSSnapshotConstructor(
 
   uint32_t totalLength = mDatastore->GetLength();
 
-  int64_t initialUsage = mDatastore->GetUsage();
+  int64_t usage = mDatastore->GetUsage();
 
-  int64_t peakUsage = initialUsage;
+  int64_t peakUsage = usage;
 
   if (aIncreasePeakUsage) {
     int64_t size =
@@ -5575,7 +5575,7 @@ mozilla::ipc::IPCResult Database::RecvPBackgroundLSSnapshotConstructor(
   bool hasOtherProcessObservers = mDatastore->HasOtherProcessObservers(this);
 
   snapshot->Init(loadedItems, std::move(unknownItems), nextLoadIndex,
-                 totalLength, initialUsage, peakUsage, loadState,
+                 totalLength, usage, peakUsage, loadState,
                  hasOtherProcessDatabases, hasOtherProcessObservers);
 
   RegisterSnapshot(snapshot);
@@ -5583,7 +5583,7 @@ mozilla::ipc::IPCResult Database::RecvPBackgroundLSSnapshotConstructor(
   aInitInfo->addKeyToUnknownItems() = addKeyToUnknownItems;
   aInitInfo->itemInfos() = std::move(itemInfos);
   aInitInfo->totalLength() = totalLength;
-  aInitInfo->initialUsage() = initialUsage;
+  aInitInfo->usage() = usage;
   aInitInfo->peakUsage() = peakUsage;
   aInitInfo->loadState() = loadState;
   aInitInfo->hasOtherProcessDatabases() = hasOtherProcessDatabases;
diff --git a/dom/localstorage/LSSnapshot.cpp b/dom/localstorage/LSSnapshot.cpp
index 027220ec539d..412aeeef7d28 100644
--- a/dom/localstorage/LSSnapshot.cpp
+++ b/dom/localstorage/LSSnapshot.cpp
@@ -135,7 +135,7 @@ LSSnapshot::LSSnapshot(LSDatabase* aDatabase)
       mActor(nullptr),
       mInitLength(0),
       mLength(0),
-      mExactUsage(0),
+      mUsage(0),
       mPeakUsage(0),
       mLoadState(LoadState::Initial),
       mHasOtherProcessDatabases(false),
@@ -212,7 +212,7 @@ nsresult LSSnapshot::Init(const nsAString& aKey,
     MOZ_ASSERT(loadState == LoadState::AllOrderedItems);
   }
 
-  mExactUsage = aInitInfo.initialUsage();
+  mUsage = aInitInfo.usage();
   mPeakUsage = aInitInfo.peakUsage();
 
   mLoadState = aInitInfo.loadState();
@@ -597,7 +597,7 @@ int64_t LSSnapshot::GetUsage() const {
   MOZ_ASSERT(mInitialized);
   MOZ_ASSERT(!mSentFinish);
 
-  return mExactUsage;
+  return mUsage;
 }
 
 void LSSnapshot::ScheduleStableStateCallback() {
@@ -894,13 +894,13 @@ nsresult LSSnapshot::UpdateUsage(int64_t aDelta) {
   AssertIsOnOwningThread();
   MOZ_ASSERT(mDatabase);
   MOZ_ASSERT(mActor);
-  MOZ_ASSERT(mPeakUsage >= mExactUsage);
+  MOZ_ASSERT(mPeakUsage >= mUsage);
   MOZ_ASSERT(mInitialized);
   MOZ_ASSERT(!mSentFinish);
 
-  int64_t newExactUsage = mExactUsage + aDelta;
-  if (newExactUsage > mPeakUsage) {
-    const int64_t minSize = newExactUsage - mPeakUsage;
+  int64_t newUsage = mUsage + aDelta;
+  if (newUsage > mPeakUsage) {
+    const int64_t minSize = newUsage - mPeakUsage;
 
     int64_t size;
     if (NS_WARN_IF(!mActor->SendIncreasePeakUsage(minSize, &size))) {
@@ -916,7 +916,7 @@ nsresult LSSnapshot::UpdateUsage(int64_t aDelta) {
     mPeakUsage += size;
   }
 
-  mExactUsage = newExactUsage;
+  mUsage = newUsage;
   return NS_OK;
 }
 
diff --git a/dom/localstorage/LSSnapshot.h b/dom/localstorage/LSSnapshot.h
index 23f1eb788405..b33646b099d6 100644
--- a/dom/localstorage/LSSnapshot.h
+++ b/dom/localstorage/LSSnapshot.h
@@ -103,7 +103,7 @@ class LSSnapshot final : public nsIRunnable {
 
   uint32_t mInitLength;
   uint32_t mLength;
-  int64_t mExactUsage;
+  int64_t mUsage;
   int64_t mPeakUsage;
 
   LoadState mLoadState;
diff --git a/dom/localstorage/PBackgroundLSDatabase.ipdl b/dom/localstorage/PBackgroundLSDatabase.ipdl
index 53958706d713..9a4402c97edb 100644
--- a/dom/localstorage/PBackgroundLSDatabase.ipdl
+++ b/dom/localstorage/PBackgroundLSDatabase.ipdl
@@ -50,12 +50,12 @@ struct LSSnapshotInitInfo
    * The current amount of LocalStorage usage as measured by the summing the
    * nsString Length() of both the key and the value over all stored pairs.
    */
-  int64_t initialUsage;
+  int64_t usage;
 
   /**
    * The amount of storage allowed to be used by the Snapshot without requesting
-   * more storage space via IncreasePeakUsage.  This is the `initialUsage` plus
-   * 0 or more bytes of space.  If space was available, the increase will be the
+   * more storage space via IncreasePeakUsage.  This is the `usage` plus 0 or
+   * more bytes of space.  If space was available, the increase will be the
    * `minSize` from the PBackgroundLSSnapshot constructor plus the configured
    * pre-increment (via "dom.storage.snapshot_peak_usage.initial_preincrement").
    * If the LocalStorage total usage was already close to the limit, then the