diff --git a/js/xpconnect/src/XPCComponents.cpp b/js/xpconnect/src/XPCComponents.cpp
index 2ab8b65d3a72..45eb639824f7 100644
--- a/js/xpconnect/src/XPCComponents.cpp
+++ b/js/xpconnect/src/XPCComponents.cpp
@@ -3021,7 +3021,7 @@ nsXPCComponents_Utils::GetCompartmentLocation(HandleValue val,
     obj = js::CheckedUnwrap(obj);
     MOZ_ASSERT(obj);
 
-    result = xpc::CompartmentPrivate::Get(obj)->GetLocation();
+    result = xpc::RealmPrivate::Get(obj)->GetLocation();
     return NS_OK;
 }
 
diff --git a/js/xpconnect/src/XPCJSRuntime.cpp b/js/xpconnect/src/XPCJSRuntime.cpp
index 2b0a62abf6b8..5d2ecd60f030 100644
--- a/js/xpconnect/src/XPCJSRuntime.cpp
+++ b/js/xpconnect/src/XPCJSRuntime.cpp
@@ -206,14 +206,14 @@ RealmPrivate::RealmPrivate(JS::Realm* realm)
 
 static bool
 TryParseLocationURICandidate(const nsACString& uristr,
-                             CompartmentPrivate::LocationHint aLocationHint,
+                             RealmPrivate::LocationHint aLocationHint,
                              nsIURI** aURI)
 {
     static NS_NAMED_LITERAL_CSTRING(kGRE, "resource://gre/");
     static NS_NAMED_LITERAL_CSTRING(kToolkit, "chrome://global/");
     static NS_NAMED_LITERAL_CSTRING(kBrowser, "chrome://browser/");
 
-    if (aLocationHint == CompartmentPrivate::LocationHintAddon) {
+    if (aLocationHint == RealmPrivate::LocationHintAddon) {
         // Blacklist some known locations which are clearly not add-on related.
         if (StringBeginsWith(uristr, kGRE) ||
             StringBeginsWith(uristr, kToolkit) ||
@@ -249,8 +249,9 @@ TryParseLocationURICandidate(const nsACString& uristr,
     return true;
 }
 
-bool CompartmentPrivate::TryParseLocationURI(CompartmentPrivate::LocationHint aLocationHint,
-                                             nsIURI** aURI)
+bool
+RealmPrivate::TryParseLocationURI(RealmPrivate::LocationHint aLocationHint,
+                                  nsIURI** aURI)
 {
     if (!aURI)
         return false;
@@ -1089,13 +1090,13 @@ GetCompartmentName(JSCompartment* c, nsCString& name, int* anonymizeID,
             name.AssignLiteral("(unknown)");
         }
 
-        // If the compartment's location (name) differs from the principal's
-        // script location, append the compartment's location to allow
-        // differentiation of multiple compartments owned by the same principal
-        // (e.g. components owned by the system or null principal).
-        CompartmentPrivate* compartmentPrivate = CompartmentPrivate::Get(c);
-        if (compartmentPrivate) {
-            const nsACString& location = compartmentPrivate->GetLocation();
+        // If the realm's location (name) differs from the principal's script
+        // location, append the realm's location to allow differentiation of
+        // multiple realms owned by the same principal (e.g. components owned
+        // by the system or null principal).
+        RealmPrivate* realmPrivate = RealmPrivate::Get(realm);
+        if (realmPrivate) {
+            const nsACString& location = realmPrivate->GetLocation();
             if (!location.IsEmpty() && !location.Equals(name)) {
                 name.AppendLiteral(", ");
                 name.Append(location);
diff --git a/js/xpconnect/src/nsXPConnect.cpp b/js/xpconnect/src/nsXPConnect.cpp
index 68c68f2f1198..70ea10448944 100644
--- a/js/xpconnect/src/nsXPConnect.cpp
+++ b/js/xpconnect/src/nsXPConnect.cpp
@@ -964,14 +964,14 @@ void
 SetLocationForGlobal(JSObject* global, const nsACString& location)
 {
     MOZ_ASSERT(global);
-    CompartmentPrivate::Get(global)->SetLocation(location);
+    RealmPrivate::Get(global)->SetLocation(location);
 }
 
 void
 SetLocationForGlobal(JSObject* global, nsIURI* locationURI)
 {
     MOZ_ASSERT(global);
-    CompartmentPrivate::Get(global)->SetLocationURI(locationURI);
+    RealmPrivate::Get(global)->SetLocationURI(locationURI);
 }
 
 } // namespace xpc
diff --git a/js/xpconnect/src/xpcprivate.h b/js/xpconnect/src/xpcprivate.h
index 110c874f5a14..498f85690188 100644
--- a/js/xpconnect/src/xpcprivate.h
+++ b/js/xpconnect/src/xpcprivate.h
@@ -2834,11 +2834,6 @@ class CompartmentPrivate
     CompartmentPrivate(const CompartmentPrivate&) = delete;
 
 public:
-    enum LocationHint {
-        LocationHintRegular,
-        LocationHintAddon
-    };
-
     explicit CompartmentPrivate(JSCompartment* c);
 
     ~CompartmentPrivate();
@@ -2911,48 +2906,6 @@ public:
     // by a security wrapper. See XrayWrapper.cpp.
     bool wrapperDenialWarnings[WrapperDenialTypeCount];
 
-    const nsACString& GetLocation() {
-        if (location.IsEmpty() && locationURI) {
-
-            nsCOMPtr<nsIXPConnectWrappedJS> jsLocationURI =
-                 do_QueryInterface(locationURI);
-            if (jsLocationURI) {
-                // We cannot call into JS-implemented nsIURI objects, because
-                // we are iterating over the JS heap at this point.
-                location =
-                    NS_LITERAL_CSTRING("<JS-implemented nsIURI location>");
-            } else if (NS_FAILED(locationURI->GetSpec(location))) {
-                location = NS_LITERAL_CSTRING("<unknown location>");
-            }
-        }
-        return location;
-    }
-    bool GetLocationURI(nsIURI** aURI) {
-        return GetLocationURI(LocationHintRegular, aURI);
-    }
-    bool GetLocationURI(LocationHint aLocationHint, nsIURI** aURI) {
-        if (locationURI) {
-            nsCOMPtr<nsIURI> rval = locationURI;
-            rval.forget(aURI);
-            return true;
-        }
-        return TryParseLocationURI(aLocationHint, aURI);
-    }
-    void SetLocation(const nsACString& aLocation) {
-        if (aLocation.IsEmpty())
-            return;
-        if (!location.IsEmpty() || locationURI)
-            return;
-        location = aLocation;
-    }
-    void SetLocationURI(nsIURI* aLocationURI) {
-        if (!aLocationURI)
-            return;
-        if (locationURI)
-            return;
-        locationURI = aLocationURI;
-    }
-
     JSObject2WrappedJSMap* GetWrappedJSMap() const { return mWrappedJSMap; }
     void UpdateWeakPointersAfterGC();
 
@@ -2961,11 +2914,7 @@ public:
     size_t SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf);
 
 private:
-    nsCString location;
-    nsCOMPtr<nsIURI> locationURI;
     JSObject2WrappedJSMap* mWrappedJSMap;
-
-    bool TryParseLocationURI(LocationHint aType, nsIURI** aURI);
 };
 
 bool IsUniversalXPConnectEnabled(JSCompartment* compartment);
@@ -2984,13 +2933,18 @@ CrashIfNotInAutomation()
 //
 // Following the ECMAScript spec, a realm contains a global (e.g. an inner
 // Window) and its associated scripts and objects; a compartment may contain
-// several same-origin, same-principal realms.
+// several same-origin realms.
 class RealmPrivate
 {
     RealmPrivate() = delete;
     RealmPrivate(const RealmPrivate&) = delete;
 
 public:
+    enum LocationHint {
+        LocationHintRegular,
+        LocationHintAddon
+    };
+
     explicit RealmPrivate(JS::Realm* realm);
 
     static RealmPrivate* Get(JS::Realm* realm)
@@ -3015,6 +2969,55 @@ public:
     // Our XPCWrappedNativeScope. This is non-null if and only if this is an
     // XPConnect realm.
     XPCWrappedNativeScope* scope;
+
+    const nsACString& GetLocation() {
+        if (location.IsEmpty() && locationURI) {
+
+            nsCOMPtr<nsIXPConnectWrappedJS> jsLocationURI =
+                 do_QueryInterface(locationURI);
+            if (jsLocationURI) {
+                // We cannot call into JS-implemented nsIURI objects, because
+                // we are iterating over the JS heap at this point.
+                location =
+                    NS_LITERAL_CSTRING("<JS-implemented nsIURI location>");
+            } else if (NS_FAILED(locationURI->GetSpec(location))) {
+                location = NS_LITERAL_CSTRING("<unknown location>");
+            }
+        }
+        return location;
+    }
+    bool GetLocationURI(LocationHint aLocationHint, nsIURI** aURI) {
+        if (locationURI) {
+            nsCOMPtr<nsIURI> rval = locationURI;
+            rval.forget(aURI);
+            return true;
+        }
+        return TryParseLocationURI(aLocationHint, aURI);
+    }
+    bool GetLocationURI(nsIURI** aURI) {
+        return GetLocationURI(LocationHintRegular, aURI);
+    }
+
+    void SetLocation(const nsACString& aLocation) {
+        if (aLocation.IsEmpty())
+            return;
+        if (!location.IsEmpty() || locationURI)
+            return;
+        location = aLocation;
+    }
+    void SetLocationURI(nsIURI* aLocationURI) {
+        if (!aLocationURI)
+            return;
+        if (locationURI)
+            return;
+        locationURI = aLocationURI;
+    }
+
+private:
+    nsCString location;
+    nsCOMPtr<nsIURI> locationURI;
+
+    bool TryParseLocationURI(LocationHint aType, nsIURI** aURI);
 };
 
 inline XPCWrappedNativeScope*