diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 75d8849fc..d7ef91a81 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -15019,7 +15019,7 @@ interface Window extends EventTarget, WindowTimers, WindowSessionStorage, Window
     onvrdisplaypointerunrestricted: ((this: Window, ev: Event) => any) | null;
     onvrdisplaypresentchange: ((this: Window, ev: Event) => any) | null;
     onwaiting: ((this: Window, ev: Event) => any) | null;
-    readonly opener: any;
+    opener: any;
     readonly orientation: string | number;
     readonly outerHeight: number;
     readonly outerWidth: number;
diff --git a/inputfiles/overridingTypes.json b/inputfiles/overridingTypes.json
index f7cb508f7..4058d9448 100644
--- a/inputfiles/overridingTypes.json
+++ b/inputfiles/overridingTypes.json
@@ -181,7 +181,8 @@
                         },
                         "opener": {
                             "name": "opener",
-                            "override-type": "any"
+                            "override-type": "any",
+                            "read-only": 0
                         },
                         "ontouchcancel": {
                             "name": "ontouchcancel",