frontend-app-api: remove experimental createExtensionTree API

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/app/src/App.tsx

@@ -27,12 +27,7 @@ import {
   RELATION_PROVIDES_API,
 } from '@backstage/catalog-model';
 import { createApp } from '@backstage/app-defaults';
-import {
-  AppRouter,
-  ConfigReader,
-  defaultConfigLoader,
-  FlatRoutes,
-} from '@backstage/core-app-api';
+import { AppRouter, FlatRoutes } from '@backstage/core-app-api';
 import {
   AlertDisplay,
   OAuthRequestDialog,
@@ -112,10 +107,6 @@ import { PuppetDbPage } from '@backstage/plugin-puppetdb';
 import { DevToolsPage } from '@backstage/plugin-devtools';
 import { customDevToolsPage } from './components/devtools/CustomDevToolsPage';
 import { CatalogUnprocessedEntitiesPage } from '@backstage/plugin-catalog-unprocessed-entities';
-import {
-  createExtensionTree,
-  ExtensionTree,
-} from '@backstage/frontend-app-api';
 
 const app = createApp({
   apis,
@@ -162,14 +153,6 @@ const app = createApp({
   },
 });
 
-/* HIGHLY EXPERIMENTAL. DO NOT USE THIS IN YOUR APP */
-let extensionTree: ExtensionTree | undefined;
-if (process.env.NODE_ENV !== 'test') {
-  extensionTree = createExtensionTree({
-    config: ConfigReader.fromConfigs(await defaultConfigLoader()),
-  });
-}
-
 const routes = (
   <FlatRoutes>
     <Route path="/" element={<Navigate to="catalog" />} />
@@ -258,10 +241,6 @@ const routes = (
       path="/tech-radar"
       element={<TechRadarPage width={1500} height={800} />}
     />
-    {
-      /* HIGHLY EXPERIMENTAL. DO NOT USE THIS IN YOUR APP */ extensionTree?.getRootRoutes() ??
-        null
-    }
     <Route path="/lighthouse" element={<LighthousePage />} />
     <Route path="/api-docs" element={<ApiExplorerPage />} />
     <Route path="/gcp-projects" element={<GcpProjectsPage />} />
@@ -302,7 +281,7 @@ export default app.createRoot(
     <OAuthRequestDialog />
     <AppRouter>
       <VisitListener />
-      <Root extensionTree={extensionTree}>{routes}</Root>
+      <Root>{routes}</Root>
     </AppRouter>
   </>,
 );

packages/app/src/components/Root/Root.tsx

@@ -84,7 +84,6 @@ const SidebarLogo = () => {
 
 export const Root = ({
   children,
-  extensionTree,
 }: PropsWithChildren<{ extensionTree?: ExtensionTree }>) => (
   <SidebarPage>
     <Sidebar>
@@ -166,10 +165,6 @@ export const Root = ({
             to="cost-insights"
             text="Cost Insights"
           />
-          {
-            /* HIGHLY EXPERIMENTAL. DO NOT USE THIS IN YOUR APP */ extensionTree?.getSidebarItems() ??
-              null
-          }
           <SidebarItem icon={Score} to="score-board" text="Score board" />
         </SidebarScrollWrapper>
         <SidebarDivider />