diff --git a/build/lib/extensions.ts b/build/lib/extensions.ts
index d11ecac3442..3578bf1bd0b 100644
--- a/build/lib/extensions.ts
+++ b/build/lib/extensions.ts
@@ -263,19 +263,38 @@ const webBuiltInExtensions: IBuiltInExtension[] = productJson.webBuiltInExtensio
 
 type ExtensionKind = 'ui' | 'workspace' | 'web';
 interface IExtensionManifest {
-	main: string;
-	browser: string;
+	main?: string;
+	browser?: string;
 	extensionKind?: ExtensionKind | ExtensionKind[];
+	extensionPack?: string[];
+	extensionDependencies?: string[];
+	contributes?: { [id: string]: any };
 }
 /**
  * Loosely based on `getExtensionKind` from `src/vs/workbench/services/extensions/common/extensionManifestPropertiesService.ts`
  */
 function isWebExtension(manifest: IExtensionManifest): boolean {
+	if (Boolean(manifest.browser)) {
+		return true;
+	}
+	if (Boolean(manifest.main)) {
+		return false;
+	}
+	// neither browser nor main
 	if (typeof manifest.extensionKind !== 'undefined') {
 		const extensionKind = Array.isArray(manifest.extensionKind) ? manifest.extensionKind : [manifest.extensionKind];
-		return (extensionKind.indexOf('web') >= 0);
+		if (extensionKind.indexOf('web') >= 0) {
+			return true;
+		}
 	}
-	return (!Boolean(manifest.main) || Boolean(manifest.browser));
+	if (typeof manifest.contributes !== 'undefined') {
+		for (const id of ['debuggers', 'terminal', 'typescriptServerPlugins']) {
+			if (manifest.contributes.hasOwnProperty(id)) {
+				return false;
+			}
+		}
+	}
+	return true;
 }
 
 export function packageLocalExtensionsStream(forWeb: boolean): Stream {