diff --git a/src/extensions.ts b/src/extensions.ts
index 1d8918e4..4381c0c5 100644
--- a/src/extensions.ts
+++ b/src/extensions.ts
@@ -93,6 +93,11 @@ export async function registerRemoteExtension (directory: string): Promise<Regis
   return registerExtension(manifest, ExtensionHostKind.Remote, { path: directory })
 }
 
+const extensions: IExtension[] = []
+export function getExtensionManifests (): IExtension[] {
+  return extensions
+}
+
 export function registerExtension (manifest: IExtensionManifest, extHostKind: ExtensionHostKind.LocalProcess, params?: RegisterExtensionParams): RegisterLocalProcessExtensionResult
 export function registerExtension (manifest: IExtensionManifest, extHostKind: ExtensionHostKind.LocalWebWorker, params?: RegisterExtensionParams): RegisterLocalExtensionResult
 export function registerExtension (manifest: IExtensionManifest, extHostKind: ExtensionHostKind.Remote, params?: RegisterRemoteExtensionParams): RegisterRemoteExtensionResult
@@ -127,6 +132,10 @@ export function registerExtension (manifest: IExtensionManifest, extHostKind?: E
       changelogUrl: changelogPath != null ? URI.joinPath(realLocation, changelogPath) : undefined
     }
 
+    if (extHostKind !== ExtensionHostKind.Remote) {
+      extensions.push(extension)
+    }
+
     await deltaExtensions({ toAdd: [extension], toRemove: [] })
 
     return extension
@@ -139,6 +148,12 @@ export function registerExtension (manifest: IExtensionManifest, extHostKind?: E
     },
     async dispose () {
       const extension = await addExtensionPromise
+
+      const index = extensions.indexOf(extension)
+      if (index >= 0) {
+        extensions.splice(extensions.indexOf(extension), 1)
+      }
+
       await deltaExtensions({ toAdd: [], toRemove: [extension] })
     }
   }
diff --git a/src/service-override/extensionGallery.ts b/src/service-override/extensionGallery.ts
index 458eb042..daea33b3 100644
--- a/src/service-override/extensionGallery.ts
+++ b/src/service-override/extensionGallery.ts
@@ -13,8 +13,7 @@ import { WebExtensionsScannerService } from 'vs/workbench/services/extensionMana
 import { IExtensionRecommendationNotificationService } from 'vs/platform/extensionRecommendations/common/extensionRecommendations'
 import { IIgnoredExtensionsManagementService, IgnoredExtensionsManagementService } from 'vs/platform/userDataSync/common/ignoredExtensions'
 import { ExtensionManifestPropertiesService, IExtensionManifestPropertiesService } from 'vs/workbench/services/extensions/common/extensionManifestPropertiesService'
-import { IBuiltinExtensionsScannerService } from 'vs/platform/extensions/common/extensions'
-import { BuiltinExtensionsScannerService } from 'vs/workbench/services/extensionManagement/browser/builtinExtensionsScannerService'
+import { IBuiltinExtensionsScannerService, IExtension } from 'vs/platform/extensions/common/extensions'
 import { ExtensionIgnoredRecommendationsService } from 'vs/workbench/services/extensionRecommendations/common/extensionIgnoredRecommendationsService'
 import { IWorkspaceExtensionsConfigService, WorkspaceExtensionsConfigService } from 'vs/workbench/services/extensionRecommendations/common/workspaceExtensionsConfig'
 import { ExtensionRecommendationNotificationService } from 'vs/workbench/contrib/extensions/browser/extensionRecommendationNotificationService'
@@ -29,6 +28,7 @@ import { IRemoteAgentService } from 'vs/workbench/services/remote/common/remoteA
 import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation'
 import { ILabelService } from 'vs/platform/label/common/label'
 import { registerAssets } from '../assets'
+import { getExtensionManifests } from '../extensions'
 
 // plugin-import-meta-asset only allows relative paths
 registerAssets({
@@ -57,6 +57,14 @@ class ExtensionManagementServerServiceOverride extends ExtensionManagementServer
   }
 }
 
+class CustomBuiltinExtensionsScannerService implements IBuiltinExtensionsScannerService {
+  _serviceBrand: undefined
+
+  async scanBuiltinExtensions (): Promise<IExtension[]> {
+    return getExtensionManifests()
+  }
+}
+
 export interface ExtensionGalleryOptions {
   /**
    * Whether we should only allow for web extensions to be installed, this is generally
@@ -78,7 +86,7 @@ export default function getServiceOverride (options: ExtensionGalleryOptions = {
     [IIgnoredExtensionsManagementService.toString()]: new SyncDescriptor(IgnoredExtensionsManagementService, [], true),
     [IExtensionManifestPropertiesService.toString()]: new SyncDescriptor(ExtensionManifestPropertiesService, [], true),
     [IExtensionManagementService.toString()]: new SyncDescriptor(ExtensionManagementService, [], true),
-    [IBuiltinExtensionsScannerService.toString()]: new SyncDescriptor(BuiltinExtensionsScannerService, [], true),
+    [IBuiltinExtensionsScannerService.toString()]: new SyncDescriptor(CustomBuiltinExtensionsScannerService, [], true),
     [IWorkspaceExtensionsConfigService.toString()]: new SyncDescriptor(WorkspaceExtensionsConfigService, [], true),
     [IExtensionTipsService.toString()]: new SyncDescriptor(ExtensionTipsService, [], true),
     [IRemoteUserDataProfilesService.toString()]: new SyncDescriptor(RemoteUserDataProfilesService, [], true),