diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index c87228d0f..e56291e41 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -18028,7 +18028,7 @@ type GLuint64 = number;
 type HTMLOrSVGImageElement = HTMLImageElement | SVGImageElement;
 type HTMLOrSVGScriptElement = HTMLScriptElement | SVGScriptElement;
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
-type HeadersInit = string[][] | Record<string, string> | Headers;
+type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
 type ImageBitmapSource = CanvasImageSource | Blob | ImageData;
 type InsertPosition = "beforebegin" | "afterbegin" | "beforeend" | "afterend";
diff --git a/baselines/serviceworker.generated.d.ts b/baselines/serviceworker.generated.d.ts
index a414b84ec..6c489a793 100644
--- a/baselines/serviceworker.generated.d.ts
+++ b/baselines/serviceworker.generated.d.ts
@@ -5527,7 +5527,7 @@ type GLsizeiptr = number;
 type GLuint = number;
 type GLuint64 = number;
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
-type HeadersInit = string[][] | Record<string, string> | Headers;
+type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
 type ImageBitmapSource = CanvasImageSource | Blob | ImageData;
 type Int32List = Int32Array | GLint[];
diff --git a/baselines/sharedworker.generated.d.ts b/baselines/sharedworker.generated.d.ts
index 94140ddb7..f76da990d 100644
--- a/baselines/sharedworker.generated.d.ts
+++ b/baselines/sharedworker.generated.d.ts
@@ -5541,7 +5541,7 @@ type GLsizeiptr = number;
 type GLuint = number;
 type GLuint64 = number;
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
-type HeadersInit = string[][] | Record<string, string> | Headers;
+type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
 type ImageBitmapSource = CanvasImageSource | Blob | ImageData;
 type Int32List = Int32Array | GLint[];
diff --git a/baselines/webworker.generated.d.ts b/baselines/webworker.generated.d.ts
index e8bebc660..f9a5b1e88 100644
--- a/baselines/webworker.generated.d.ts
+++ b/baselines/webworker.generated.d.ts
@@ -5832,7 +5832,7 @@ type GLsizeiptr = number;
 type GLuint = number;
 type GLuint64 = number;
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
-type HeadersInit = string[][] | Record<string, string> | Headers;
+type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
 type ImageBitmapSource = CanvasImageSource | Blob | ImageData;
 type Int32List = Int32Array | GLint[];
diff --git a/inputfiles/addedTypes.jsonc b/inputfiles/addedTypes.jsonc
index 17f68b612..58d4a1955 100644
--- a/inputfiles/addedTypes.jsonc
+++ b/inputfiles/addedTypes.jsonc
@@ -1212,6 +1212,13 @@
                 "name": "InsertPosition"
             },
             {
+                "type": {
+                    "0": {
+                        "subtype": {
+                            "overrideType": "[string, string]"
+                        }
+                    }
+                },
                 "additionalTypes": ["Headers"],
                 "name": "HeadersInit"
             },