diff --git a/metadata-generator/src/TSEmitter/TypeSpec.cpp b/metadata-generator/src/TSEmitter/TypeSpec.cpp
index ad65bbb62..3dcdee653 100644
--- a/metadata-generator/src/TSEmitter/TypeSpec.cpp
+++ b/metadata-generator/src/TSEmitter/TypeSpec.cpp
@@ -66,7 +66,8 @@ std::string TSFile::typeToString(const TypeSpec& type, bool isStatic, bool isRet
       result += ") => ";
       result += typeToString(*type.callbackReturn, false, true);
       if (type.isNullable) {
-        result += " | null";
+        // `() => T | null` would make the return type nullable instead.
+        result = "(" + result + ") | null";
       }
       break;
     }
diff --git a/packages/objc-node-api/index.d.ts b/packages/objc-node-api/index.d.ts
index 021f11abb..f6b1e610f 100644
--- a/packages/objc-node-api/index.d.ts
+++ b/packages/objc-node-api/index.d.ts
@@ -9,6 +9,27 @@ declare global {
 
   class NativeObject implements interop.PointerObject {
     readonly __brand__: interop.PointerObject["__brand__"];
+
+    /**
+     * Registers an Objective-C subclass of this class. Functions in `methods`
+     * override the same-named members of this class and of
+     * `options.protocols`; other names are only callable from Objective-C
+     * when listed in `options.exposedMethods`. The returned class cannot
+     * itself be extended.
+     */
+    static extend<
+      // deno-lint-ignore no-explicit-any
+      This extends abstract new (...args: any) => any,
+      // Inferred rather than annotated so that names absent from the class
+      // (protocol and exposed methods) are not excess properties. `& object`
+      // keeps literals sharing no name with the class from failing the weak
+      // type check against the all-optional Partial.
+      Methods extends Partial<InstanceType<This>> & object,
+    >(
+      this: This,
+      methods: Methods & ThisType<InstanceType<This> & Methods>,
+      options?: objc.ExtendOptions,
+    ): This;
   }
 
   namespace objc {
@@ -25,6 +46,19 @@ declare global {
       ptr: interop.Pointer,
       size: number,
     ): ArrayBuffer;
+
+    export interface ExposedMethod {
+      returns?: unknown;
+      params?: unknown[];
+    }
+
+    export interface ExtendOptions {
+      /** Objective-C class name; a numeric suffix is added if it is taken. */
+      name?: string;
+      protocols?: unknown[];
+      /** Keyed by method name in `methods`. */
+      exposedMethods?: Record<string, ExposedMethod>;
+    }
   }
 
   namespace interop {
diff --git a/packages/react-native/cli/configure.js b/packages/react-native/cli/configure.js
index e2e271e10..79c4a015d 100755
--- a/packages/react-native/cli/configure.js
+++ b/packages/react-native/cli/configure.js
@@ -26,8 +26,9 @@ function printNextSteps() {
   console.log('  iOS     : cd ios && RCT_NEW_ARCH_ENABLED=1 USE_HERMES=1 pod install');
   console.log('  Android : npx react-native run-android');
   console.log('');
-  console.log('  Android typings are generated on demand:');
-  console.log('    cd android && ./gradlew generateNativeScriptTypingsDebug -PnsGenerateTypings=true');
+  console.log('  Android typings are written to types/android/ on the first build');
+  console.log('  (opt out with -PnsGenerateTypings=false). To generate them on their own:');
+  console.log('    cd android && ./gradlew generateNativeScriptTypingsDebug');
 }
 
 function configure(argv = process.argv.slice(2)) {