diff --git a/.changeset/fluffy-otters-cry.md b/.changeset/fluffy-otters-cry.md
new file mode 100644
index 0000000000..fd24a0bb47
--- /dev/null
+++ b/.changeset/fluffy-otters-cry.md
@@ -0,0 +1,5 @@
+---
+'@backstage/frontend-app-api': minor
+---
+
+Use an app plugin for built-in extension app node specs.
diff --git a/.changeset/thirty-eagles-run.md b/.changeset/thirty-eagles-run.md
new file mode 100644
index 0000000000..10ca1af381
--- /dev/null
+++ b/.changeset/thirty-eagles-run.md
@@ -0,0 +1,5 @@
+---
+'@backstage/frontend-app-api': minor
+---
+
+The `AppNodeSpec.plugin` property is now required.
diff --git a/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts b/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts
index 5fa22536f8..57ec7b23f3 100644
--- a/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts
+++ b/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts
@@ -27,6 +27,7 @@ import {
   createExtensionBlueprint,
   createExtensionDataRef,
   createExtensionInput,
+  createFrontendPlugin,
 } from '@backstage/frontend-plugin-api';
 import {
   createAppNodeInstance,
@@ -59,7 +60,7 @@ function makeSpec<TConfig, TConfigInput>(
     attachTo: extension.attachTo,
     disabled: extension.disabled,
     extension: extension as Extension<unknown, unknown>,
-    plugin: undefined,
+    plugin: createFrontendPlugin({ pluginId: 'app' }),
     ...spec,
   };
 }
diff --git a/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.test.ts b/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.test.ts
index 979c851a47..83abcf3dc4 100644
--- a/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.test.ts
+++ b/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.test.ts
@@ -68,6 +68,9 @@ describe('resolveAppNodeSpecs', () => {
         extension: a,
         attachTo: { id: 'root', input: 'default' },
         disabled: true,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
     ]);
   });
@@ -87,12 +90,18 @@ describe('resolveAppNodeSpecs', () => {
         extension: a,
         attachTo: { id: 'root', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
       {
         id: 'b',
         extension: b,
         attachTo: { id: 'root', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
     ]);
   });
@@ -120,6 +129,9 @@ describe('resolveAppNodeSpecs', () => {
         extension: b,
         attachTo: { id: 'derp', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
       {
         id: 'test/a',
@@ -204,12 +216,18 @@ describe('resolveAppNodeSpecs', () => {
         extension: b,
         attachTo: { id: 'root', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
       {
         id: 'a',
         extension: a,
         attachTo: { id: 'root', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
     ]);
   });
@@ -238,42 +256,63 @@ describe('resolveAppNodeSpecs', () => {
         extension: e,
         attachTo: { id: 'root', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
       {
         id: 'd',
         extension: d,
         attachTo: { id: 'root', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
       {
         id: 'c',
         extension: c,
         attachTo: { id: 'root', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
       {
         id: 'a',
         extension: a,
         attachTo: { id: 'root', input: 'default' },
         disabled: true,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
       {
         id: 'b',
         extension: b,
         attachTo: { id: 'root', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
       {
         id: 'f',
         extension: f,
         attachTo: { id: 'root', input: 'default' },
         disabled: false,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
       {
         id: 'g',
         extension: g,
         attachTo: { id: 'root', input: 'default' },
         disabled: true,
+        config: undefined,
+        plugin: expect.any(Object),
+        source: expect.any(Object),
       },
     ]);
   });
diff --git a/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.ts b/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.ts
index 4788734800..f9ce7387c2 100644
--- a/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.ts
+++ b/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.ts
@@ -14,7 +14,11 @@
  * limitations under the License.
  */
 
-import { Extension, FrontendFeature } from '@backstage/frontend-plugin-api';
+import {
+  createFrontendPlugin,
+  Extension,
+  FrontendFeature,
+} from '@backstage/frontend-plugin-api';
 import { ExtensionParameters } from './readAppExtensionsConfig';
 import { AppNodeSpec } from '@backstage/frontend-plugin-api';
 import { OpaqueFrontendPlugin } from '@internal/frontend';
@@ -87,6 +91,12 @@ export function resolveAppNodeSpecs(options: {
     );
   }
 
+  const appPlugin =
+    plugins.find(plugin => plugin.id === 'app') ??
+    createFrontendPlugin({
+      pluginId: 'app',
+    });
+
   const configuredExtensions = [
     ...pluginExtensions.map(({ plugin, ...extension }) => {
       const internalExtension = toInternalExtension(extension);
@@ -106,8 +116,8 @@ export function resolveAppNodeSpecs(options: {
       return {
         extension: internalExtension,
         params: {
-          source: undefined,
-          plugin: undefined,
+          source: appPlugin,
+          plugin: appPlugin,
           attachTo: internalExtension.attachTo,
           disabled: internalExtension.disabled,
           config: undefined as unknown,
diff --git a/packages/frontend-app-api/src/tree/resolveAppTree.test.ts b/packages/frontend-app-api/src/tree/resolveAppTree.test.ts
index e93d311f8d..f1161b202e 100644
--- a/packages/frontend-app-api/src/tree/resolveAppTree.test.ts
+++ b/packages/frontend-app-api/src/tree/resolveAppTree.test.ts
@@ -18,6 +18,7 @@ import {
   coreExtensionData,
   createExtension,
   createExtensionInput,
+  createFrontendPlugin,
   Extension,
 } from '@backstage/frontend-plugin-api';
 import { resolveAppTree } from './resolveAppTree';
@@ -37,6 +38,7 @@ const baseSpec = {
   extension,
   attachTo: { id: 'nonexistent', input: 'nonexistent' },
   disabled: false,
+  plugin: createFrontendPlugin({ pluginId: 'app' }),
 };
 
 describe('buildAppTree', () => {
@@ -284,8 +286,20 @@ describe('buildAppTree', () => {
       ) as Extension<unknown, unknown>;
 
       const tree = resolveAppTree('a', [
-        { attachTo: e1.attachTo, id: 'a', extension: e1, disabled: false },
-        { attachTo: e2.attachTo, id: 'b', extension: e2, disabled: false },
+        {
+          attachTo: e1.attachTo,
+          id: 'a',
+          extension: e1,
+          disabled: false,
+          plugin: baseSpec.plugin,
+        },
+        {
+          attachTo: e2.attachTo,
+          id: 'b',
+          extension: e2,
+          disabled: false,
+          plugin: baseSpec.plugin,
+        },
       ]);
 
       expect(tree.root).toMatchInlineSnapshot(`
@@ -352,9 +366,27 @@ describe('buildAppTree', () => {
       ) as Extension<unknown, unknown>;
 
       const tree = resolveAppTree('test-2', [
-        { attachTo: e1.attachTo, id: e1.id, extension: e1, disabled: false },
-        { attachTo: e2.attachTo, id: e2.id, extension: e2, disabled: false },
-        { attachTo: e3.attachTo, id: e3.id, extension: e3, disabled: false },
+        {
+          attachTo: e1.attachTo,
+          id: e1.id,
+          extension: e1,
+          disabled: false,
+          plugin: baseSpec.plugin,
+        },
+        {
+          attachTo: e2.attachTo,
+          id: e2.id,
+          extension: e2,
+          disabled: false,
+          plugin: baseSpec.plugin,
+        },
+        {
+          attachTo: e3.attachTo,
+          id: e3.id,
+          extension: e3,
+          disabled: false,
+          plugin: baseSpec.plugin,
+        },
       ]);
 
       expect(tree.nodes.get('test-3')?.edges.attachedTo?.node).toBe(
diff --git a/packages/frontend-plugin-api/report.api.md b/packages/frontend-plugin-api/report.api.md
index 78c2ba361f..469733987e 100644
--- a/packages/frontend-plugin-api/report.api.md
+++ b/packages/frontend-plugin-api/report.api.md
@@ -268,7 +268,7 @@ export interface AppNodeSpec {
   // (undocumented)
   readonly id: string;
   // (undocumented)
-  readonly plugin?: FrontendPlugin;
+  readonly plugin: FrontendPlugin;
 }
 
 // @public
diff --git a/packages/frontend-plugin-api/src/apis/definitions/AppTreeApi.ts b/packages/frontend-plugin-api/src/apis/definitions/AppTreeApi.ts
index 3ce55e1525..f4fd2f3a6f 100644
--- a/packages/frontend-plugin-api/src/apis/definitions/AppTreeApi.ts
+++ b/packages/frontend-plugin-api/src/apis/definitions/AppTreeApi.ts
@@ -37,7 +37,7 @@ export interface AppNodeSpec {
   readonly extension: Extension<unknown, unknown>;
   readonly disabled: boolean;
   readonly config?: unknown;
-  readonly plugin?: FrontendPlugin;
+  readonly plugin: FrontendPlugin;
 }
 
 /**