refactor(home): bundle widget data into single extension ref

Following FormFieldBlueprint pattern, bundle component and metadata
into a single comprehensive homePageWidgetDataRef instead of outputting
them separately. This addresses review feedback about outputting data
that nothing consumes.
- Create homePageWidgetDataRef in plugin-home-react
- Update HomepageWidgetBlueprint to output bundled data
- Update HomepageBlueprint to consume bundled data and extract component
- Remove unused widgetMetadataRef export
Signed-off-by: Adam Kunicki <kunickiaj@gmail.com>

plugins/home-react/src/alpha.ts

@@ -26,7 +26,10 @@
 export { homeReactTranslationRef } from './translation';
 export {
   HomepageWidgetBlueprint,
-  widgetMetadataRef,
   type HomepageWidgetBlueprintParams,
 } from './alpha/blueprints/HomepageWidgetBlueprint';
+export {
+  homePageWidgetDataRef,
+  type HomePageWidgetData,
+} from './alpha/dataRefs';
 export type { ComponentParts, CardLayout, CardSettings } from './extensions';

plugins/home-react/src/alpha/blueprints/HomepageWidgetBlueprint.tsx

@@ -17,9 +17,7 @@
 import { lazy, ReactElement } from 'react';
 import { compatWrapper } from '@backstage/core-compat-api';
 import {
-  coreExtensionData,
   createExtensionBlueprint,
-  createExtensionDataRef,
   ExtensionBoundary,
 } from '@backstage/frontend-plugin-api';
 import {
@@ -29,6 +27,7 @@ import {
   CardSettings,
   ComponentParts,
 } from '../../extensions';
+import { homePageWidgetDataRef } from '../dataRefs';
 
 /** @alpha */
 export interface HomepageWidgetBlueprintParams {
@@ -68,18 +67,6 @@ const DEFAULT_WIDGET_ATTACH_POINT = {
   input: 'widgets',
 } as const;
 
-/**
- * Extension data ref for widget metadata.
- * @alpha
- */
-export const widgetMetadataRef = createExtensionDataRef<{
-  name?: string;
-  title?: string;
-  description?: string;
-  layout?: CardLayout;
-  settings?: CardSettings;
-}>().with({ id: 'home.widget.metadata' });
-
 /**
  * Creates widgets that can be installed into the home page grid.
  *
@@ -88,7 +75,7 @@ export const widgetMetadataRef = createExtensionDataRef<{
 export const HomepageWidgetBlueprint = createExtensionBlueprint({
   kind: 'home-widget',
   attachTo: DEFAULT_WIDGET_ATTACH_POINT,
-  output: [coreExtensionData.reactElement, widgetMetadataRef],
+  output: [homePageWidgetDataRef],
   *factory(params: HomepageWidgetBlueprintParams, { node }) {
     const isCustomizable = params.settings?.schema !== undefined;
     const LazyCard = lazy(() =>
@@ -113,11 +100,8 @@ export const HomepageWidgetBlueprint = createExtensionBlueprint({
         </ExtensionBoundary>,
       );
 
-    yield coreExtensionData.reactElement(
-      <Widget {...(params.componentProps ?? {})} />,
-    );
-
-    yield widgetMetadataRef({
+    yield homePageWidgetDataRef({
+      component: <Widget {...(params.componentProps ?? {})} />,
       name: params.name,
       title: params.title,
       description: params.description,

plugins/home-react/src/alpha/dataRefs.ts

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { createExtensionDataRef } from '@backstage/frontend-plugin-api';
+import { ReactElement } from 'react';
+import type { CardLayout, CardSettings } from '../extensions';
+
+/**
+ * Extension data for homepage widgets, bundling the rendered component
+ * with its metadata.
+ *
+ * @alpha
+ */
+export interface HomePageWidgetData {
+  /**
+   * The rendered widget component (typically a card with header, content, etc.)
+   */
+  component: ReactElement;
+  /**
+   * Optional name identifier for the widget
+   */
+  name?: string;
+  /**
+   * Optional title displayed in the widget header
+   */
+  title?: string;
+  /**
+   * Optional description shown in widget catalogs or configuration UIs
+   */
+  description?: string;
+  /**
+   * Optional layout hints for positioning and sizing
+   */
+  layout?: CardLayout;
+  /**
+   * Optional settings schema for widget configuration
+   */
+  settings?: CardSettings;
+}
+
+/**
+ * Extension data ref for homepage widgets.
+ *
+ * This follows the pattern from FormFieldBlueprint, bundling the component
+ * and metadata into a single comprehensive data ref rather than outputting
+ * them separately.
+ *
+ * @alpha
+ */
+export const homePageWidgetDataRef =
+  createExtensionDataRef<HomePageWidgetData>().with({
+    id: 'home.widget.data',
+  });