diff --git a/.github/workflows/commit_artifacts.yml b/.github/workflows/commit_artifacts.yml
index 2e5007982b1cb..08e5f8223d23a 100644
--- a/.github/workflows/commit_artifacts.yml
+++ b/.github/workflows/commit_artifacts.yml
@@ -133,10 +133,6 @@ jobs:
           mv build/oss-experimental/eslint-plugin-react-hooks/cjs/eslint-plugin-react-hooks.development.js \
             ./compiled/facebook-www/eslint-plugin-react-hooks.js
 
-          # Copy unstable_server-external-runtime.js into facebook-www
-          mv build/oss-stable/react-dom/unstable_server-external-runtime.js \
-            ./compiled/facebook-www/unstable_server-external-runtime.js
-
           # Copy react-refresh-babel.development.js into babel-plugin-react-refresh
           mv build/oss-experimental/react-refresh/cjs/react-refresh-babel.development.js \
             ./compiled/babel-plugin-react-refresh/index.js
@@ -148,7 +144,7 @@ jobs:
           mkdir -p ${BASE_FOLDER}/react-native-github/Libraries/Renderer/
           mkdir -p ${BASE_FOLDER}/RKJSModules/vendor/{scheduler,react,react-is,react-test-renderer}/
 
-          # Move React Native renderer 
+          # Move React Native renderer
           mv build/react-native/implementations/ $BASE_FOLDER/react-native-github/Libraries/Renderer/
           mv build/react-native/shims/ $BASE_FOLDER/react-native-github/Libraries/Renderer/
           mv build/facebook-react-native/scheduler/cjs/ $BASE_FOLDER/RKJSModules/vendor/scheduler/
diff --git a/scripts/rollup/build-all-release-channels.js b/scripts/rollup/build-all-release-channels.js
index 25f2652ecf562..01b8d68923628 100644
--- a/scripts/rollup/build-all-release-channels.js
+++ b/scripts/rollup/build-all-release-channels.js
@@ -168,7 +168,10 @@ function processStable(buildDir) {
       const stats = fs.statSync(filePath);
       if (!stats.isDirectory()) {
         hash.update(fs.readFileSync(filePath));
-        fs.renameSync(filePath, filePath.replace('.js', '.classic.js'));
+
+        if (fileName !== 'unstable_server-external-runtime.js') {
+          fs.renameSync(filePath, filePath.replace('.js', '.classic.js'));
+        }
       }
     }
     updatePlaceholderReactVersionInCompiledArtifacts(
@@ -242,7 +245,9 @@ function processExperimental(buildDir, version) {
       const stats = fs.statSync(filePath);
       if (!stats.isDirectory()) {
         hash.update(fs.readFileSync(filePath));
-        fs.renameSync(filePath, filePath.replace('.js', '.modern.js'));
+        if (fileName !== 'unstable_server-external-runtime.js') {
+          fs.renameSync(filePath, filePath.replace('.js', '.modern.js'));
+        }
       }
     }
     updatePlaceholderReactVersionInCompiledArtifacts(
diff --git a/scripts/rollup/build.js b/scripts/rollup/build.js
index 0851ea3b04441..1221ef3314422 100644
--- a/scripts/rollup/build.js
+++ b/scripts/rollup/build.js
@@ -56,6 +56,7 @@ const {
   NODE_PROFILING,
   BUN_DEV,
   BUN_PROD,
+  FB_WWW_BROWSER_SCRIPT,
   FB_WWW_DEV,
   FB_WWW_PROD,
   FB_WWW_PROFILING,
@@ -251,6 +252,7 @@ function getFormat(bundleType) {
     case ESM_DEV:
     case ESM_PROD:
       return `es`;
+    case FB_WWW_BROWSER_SCRIPT:
     case BROWSER_SCRIPT:
       return `iife`;
   }
@@ -280,6 +282,7 @@ function isProductionBundleType(bundleType) {
     case RN_OSS_PROFILING:
     case RN_FB_PROD:
     case RN_FB_PROFILING:
+    case FB_WWW_BROWSER_SCRIPT:
     case BROWSER_SCRIPT:
       return true;
     default:
@@ -304,6 +307,7 @@ function isProfilingBundleType(bundleType) {
     case ESM_PROD:
     case UMD_DEV:
     case UMD_PROD:
+    case FB_WWW_BROWSER_SCRIPT:
     case BROWSER_SCRIPT:
       return false;
     case FB_WWW_PROFILING:
@@ -322,10 +326,12 @@ function getBundleTypeFlags(bundleType) {
     bundleType === UMD_DEV ||
     bundleType === UMD_PROD ||
     bundleType === UMD_PROFILING;
-  const isFBWWWBundle =
+  const isFBWWWBundleAndNotBrowserScript =
     bundleType === FB_WWW_DEV ||
     bundleType === FB_WWW_PROD ||
     bundleType === FB_WWW_PROFILING;
+  const isFBWWWBundle =
+    isFBWWWBundleAndNotBrowserScript || bundleType === FB_WWW_BROWSER_SCRIPT;
   const isRNBundle =
     bundleType === RN_OSS_DEV ||
     bundleType === RN_OSS_PROD ||
@@ -339,7 +345,10 @@ function getBundleTypeFlags(bundleType) {
     bundleType === RN_FB_PROD ||
     bundleType === RN_FB_PROFILING;
 
-  const shouldStayReadable = isFBWWWBundle || isRNBundle || forcePrettyOutput;
+  const isBrowserScript = FB_WWW_BROWSER_SCRIPT || BROWSER_SCRIPT;
+
+  const shouldStayReadable =
+    isFBWWWBundleAndNotBrowserScript || isRNBundle || forcePrettyOutput;
 
   const shouldBundleDependencies =
     bundleType === UMD_DEV ||
@@ -348,9 +357,11 @@ function getBundleTypeFlags(bundleType) {
 
   return {
     isUMDBundle,
+    isFBWWWBundleAndNotBrowserScript,
     isFBWWWBundle,
     isRNBundle,
     isFBRNBundle,
+    isBrowserScript,
     shouldBundleDependencies,
     shouldStayReadable,
   };
@@ -387,7 +398,8 @@ function getPlugins(
     const isProduction = isProductionBundleType(bundleType);
     const isProfiling = isProfilingBundleType(bundleType);
 
-    const {isUMDBundle, shouldStayReadable} = getBundleTypeFlags(bundleType);
+    const {isUMDBundle, shouldStayReadable, isFBWWWBundle, isBrowserScript} =
+      getBundleTypeFlags(bundleType);
 
     const needsMinifiedByClosure = isProduction && bundleType !== ESM_PROD;
 
@@ -408,7 +420,8 @@ function getPlugins(
       needsMinifiedByClosure &&
       !isUMDBundle &&
       !sourcemapPackageExcludes.includes(entry) &&
-      !shouldStayReadable;
+      !shouldStayReadable &&
+      bundleType !== FB_WWW_BROWSER_SCRIPT;
 
     return [
       // Keep dynamic imports as externals
@@ -494,11 +507,12 @@ function getPlugins(
             language_out:
               bundleType === NODE_ES2015
                 ? 'ECMASCRIPT_2020'
-                : bundleType === BROWSER_SCRIPT
+                : isBrowserScript
                 ? 'ECMASCRIPT5'
                 : 'ECMASCRIPT5_STRICT',
             emit_use_strict:
               bundleType !== BROWSER_SCRIPT &&
+              bundleType !== FB_WWW_BROWSER_SCRIPT &&
               bundleType !== ESM_PROD &&
               bundleType !== ESM_DEV,
             env: 'CUSTOM',
@@ -697,12 +711,15 @@ async function createBundle(bundle, bundleType) {
   const format = getFormat(bundleType);
   const packageName = Packaging.getPackageName(bundle.entry);
 
-  const {isFBWWWBundle, isFBRNBundle, shouldBundleDependencies} =
-    getBundleTypeFlags(bundleType);
+  const {
+    isFBWWWBundleAndNotBrowserScript,
+    isFBRNBundle,
+    shouldBundleDependencies,
+  } = getBundleTypeFlags(bundleType);
 
   let resolvedEntry = resolveEntryFork(
     require.resolve(bundle.entry),
-    isFBWWWBundle || isFBRNBundle
+    isFBWWWBundleAndNotBrowserScript || isFBRNBundle
   );
 
   const peerGlobals = Modules.getPeerGlobals(bundle.externals, bundleType);
@@ -903,6 +920,7 @@ async function buildEverything() {
       [bundle, NODE_PROFILING],
       [bundle, BUN_DEV],
       [bundle, BUN_PROD],
+      [bundle, FB_WWW_BROWSER_SCRIPT],
       [bundle, FB_WWW_DEV],
       [bundle, FB_WWW_PROD],
       [bundle, FB_WWW_PROFILING],
diff --git a/scripts/rollup/bundles.js b/scripts/rollup/bundles.js
index 31d15ecc7b875..c4c2827b2babb 100644
--- a/scripts/rollup/bundles.js
+++ b/scripts/rollup/bundles.js
@@ -19,6 +19,7 @@ const bundleTypes = {
   NODE_PROFILING: 'NODE_PROFILING',
   BUN_DEV: 'BUN_DEV',
   BUN_PROD: 'BUN_PROD',
+  FB_WWW_BROWSER_SCRIPT: 'FB_WWW_BROWSER_SCRIPT',
   FB_WWW_DEV: 'FB_WWW_DEV',
   FB_WWW_PROD: 'FB_WWW_PROD',
   FB_WWW_PROFILING: 'FB_WWW_PROFILING',
@@ -43,6 +44,7 @@ const {
   NODE_PROFILING,
   BUN_DEV,
   BUN_PROD,
+  FB_WWW_BROWSER_SCRIPT,
   FB_WWW_DEV,
   FB_WWW_PROD,
   FB_WWW_PROFILING,
@@ -300,7 +302,7 @@ const bundles = [
 
   /******* React DOM Fizz Server External Runtime *******/
   {
-    bundleTypes: [BROWSER_SCRIPT],
+    bundleTypes: [BROWSER_SCRIPT, FB_WWW_BROWSER_SCRIPT],
     moduleType: RENDERER,
     entry: 'react-dom/unstable_server-external-runtime',
     outputPath: 'unstable_server-external-runtime.js',
@@ -1130,6 +1132,7 @@ function getFilename(bundle, bundleType) {
     case RN_FB_PROFILING:
     case RN_OSS_PROFILING:
       return `${globalName}-profiling.js`;
+    case FB_WWW_BROWSER_SCRIPT:
     case BROWSER_SCRIPT:
       return `${name}.js`;
   }
diff --git a/scripts/rollup/packaging.js b/scripts/rollup/packaging.js
index 64b1cf1735b7d..14af5bb9f0fde 100644
--- a/scripts/rollup/packaging.js
+++ b/scripts/rollup/packaging.js
@@ -29,6 +29,7 @@ const {
   NODE_PROFILING,
   BUN_DEV,
   BUN_PROD,
+  FB_WWW_BROWSER_SCRIPT,
   FB_WWW_DEV,
   FB_WWW_PROD,
   FB_WWW_PROFILING,
@@ -66,6 +67,23 @@ function getBundleOutputPath(bundle, bundleType, filename, packageName) {
     case UMD_PROD:
     case UMD_PROFILING:
       return `build/node_modules/${packageName}/umd/${filename}`;
+    case FB_WWW_BROWSER_SCRIPT: {
+      // Bundles that are served as browser scripts need to be able to be sent
+      // straight to the browser with any additional bundling. We shouldn't use
+      // a module to re-export. Depending on how they are served, they also may
+      // not go through package.json module resolution, so we shouldn't rely on
+      // that either. We should consider the output path as part of the public
+      // contract, and explicitly specify its location within the package's
+      // directory structure.
+      const outputPath = bundle.outputPath;
+      if (!outputPath) {
+        throw new Error(
+          'Bundles with type FB_WWW_BROWSER_SCRIPT must specific an explicit ' +
+          'output path.'
+        );
+      }
+      return `build/facebook-www/${outputPath}`;
+    }
     case FB_WWW_DEV:
     case FB_WWW_PROD:
     case FB_WWW_PROFILING:
diff --git a/scripts/rollup/wrappers.js b/scripts/rollup/wrappers.js
index 0b30e3b9298f6..d947818fcbb73 100644
--- a/scripts/rollup/wrappers.js
+++ b/scripts/rollup/wrappers.js
@@ -17,6 +17,7 @@ const {
   NODE_PROFILING,
   BUN_DEV,
   BUN_PROD,
+  FB_WWW_BROWSER_SCRIPT,
   FB_WWW_DEV,
   FB_WWW_PROD,
   FB_WWW_PROFILING,
@@ -442,7 +443,7 @@ function wrapBundle(
     }
   }
 
-  if (bundleType === BROWSER_SCRIPT) {
+  if (bundleType === BROWSER_SCRIPT || FB_WWW_BROWSER_SCRIPT) {
     // Bundles of type BROWSER_SCRIPT get sent straight to the browser without
     // additional processing. So we should exclude any extra wrapper comments.
     return source;