Clean up the DevTools extensions `example/README.md` and `README.md` files (#7237)

diff --git a/packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md b/packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md
index cca4832..98787fb 100644
--- a/packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md
+++ b/packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md

@@ -68,7 +68,8 @@
 
 * Fixed an issue with not detecting extensions for test files in
 subdirectories. - [#7174](https://github.com/flutter/devtools/pull/7174)
-* Add an example of creating an extension for a pure Dart package. - [#7196](https://github.com/flutter/devtools/pull/7196)
+* Added an example of creating an extension for a pure Dart package. - [#7196](https://github.com/flutter/devtools/pull/7196)
+* Updated the `example/README.md` with more complete documentation. - [#7237](https://github.com/flutter/devtools/pull/7237)
 
 ## Full commit history
 

diff --git a/packages/devtools_extensions/CHANGELOG.md b/packages/devtools_extensions/CHANGELOG.md
index c200fc9..b5be606 100644
--- a/packages/devtools_extensions/CHANGELOG.md
+++ b/packages/devtools_extensions/CHANGELOG.md

@@ -3,6 +3,7 @@
 * Bump `package:vm_service` dependency to ^14.0.0.
 * Refactor `example` directory to support more package examples.
 * Add an example of providing an extension from a pure Dart package.
+* Update the `example/README.md`.
 
 ## 0.0.13
 * Bump `package:web` to `^0.4.1`.

diff --git a/packages/devtools_extensions/README.md b/packages/devtools_extensions/README.md
index e587103..578f2c4 100644
--- a/packages/devtools_extensions/README.md
+++ b/packages/devtools_extensions/README.md

@@ -234,7 +234,8 @@
 dart run devtools_extensions build_and_copy --source=. --dest=../foo/extension/devtools
 ```
 
-Then publish your package.
+Then publish your package. When running `pub publish`, you will see a warning if you
+do not have the `config.yaml` file and a non-empty `build` directory as required.
 
 ### What if I don't want the `extension/devtools/build/` contents checked into source control?
 

diff --git a/packages/devtools_extensions/example/README.md b/packages/devtools_extensions/example/README.md
index 398a49f..8f0e1a1 100644
--- a/packages/devtools_extensions/example/README.md
+++ b/packages/devtools_extensions/example/README.md

@@ -1,18 +1,78 @@
-# Example DevTools Extension
+# DevTools extension examples
+This directory contains end-to-end examples of DevTools extensions. Each
+end-to-end example is made up of three components:
+1. **Parent package**: Dart package that provides the extension
+2. **DevTools extension**: the tool itself
+3. **End-user application**: the app that the extension is used on
 
-This is an end-to-end example of a DevTools extension, including
-- the parent `package:foo` that provides the DevTools extension to end-user
-applications (`foo/packages/foo`)
-- the end-user application (`app_that_uses_foo`) that depends on `package:foo`,
-which will trigger a load of the `package:foo` DevTools extension when debugging
-this app with DevTools
-- the `package:foo` DevTools extension (`foo/packages/foo_devtools_extension`),
-which is a Flutter web app that will be embedded in DevTools when debugging an
-app the uses `package:foo`
+## Parent package
 
+This is the Dart package that provides a DevTools extension for end-user
+applications to use in DevTools. There are multiple extension-providing pacakges
+in the `example` directory.
 
-This example will show you how to:
-1. Structure your package for optimal extension development and publishing
+- `package:foo` from `packages_with_extensions/foo/packages/foo`: a package for Flutter apps
+
+- `package:dart_foo` from `packages_with_extensions/dart_foo/packages/dart_foo`: a
+pure Dart package for Dart or Flutter apps
+
+<!-- TODO(kenz): build this example. -->
+<!-- - `package:standalone_tool` from `packages_with_extensions/dart_foo/packages/stanalone_tool`, which is a package that is strictly meant to provide a tool
+as a DevTools extension. This is different from the other packages in that it
+is not an extension shipped with an existing Dart package. It is a package
+published solely to provide a DevTools extension. -->
+
+<!-- TODO(kenz): build this example, or pull in Khan's extension. -->
+<!-- - `package:gemini_ai_tool` from `packages_with_extensions/dart_foo/packages/gemini_ai_tool`, which is a standalone tool (like `package:standalone_tool`)
+that provides an example of using the Gemini SDK to build an AI powered tool
+as a DevTools extension. -->
+
+## DevTools extension
+
+These are Flutter web apps that will be embedded in DevTools when connected to an app
+that depends on the [parent package](#parent-package).
+
+- `packages_with_extensions/foo/packages/foo_devtools_extension`: this
+is the Flutter web app whose built assets are included in `package:foo`'s
+`extension/devtools/build` directory.
+
+- `packages_with_extensions/dart_foo/packages/dart_foo_devtools_extension`: this
+is the Flutter web app whose built assets are included in `package:dart_foo`'s
+`extension/devtools/build` directory.
+
+## End-user application
+
+These are the applications that depend on the [parent package](#parent-package) and
+can connect to the [DevTools extension](#devtools-extension) provided by the parent package.
+
+### `app_that_uses_foo`
+
+This Flutter app depends on `package:foo` and `package:dart_foo`. When debugging
+`app_that_uses_foo`, or one if its `bin/` or `test/` libraries, the provided
+DevTools extensions will load in their own tab in DevTools.
+
+- `flutter run` the `app_that_uses_foo` app and open DevTools to see both the
+`package:foo` and `package:dart_foo` extensions in DevTools connected to a
+Flutter app.
+
+- Run `dart run --observe bin/script.dart` and open DevTools to see the
+`package_dart_foo` extension in DevTools connected to a Dart CLI app.
+
+<!-- TODO(kenz): uncomment once https://github.com/flutter/devtools/issues/7183 is resolved. -->
+<!-- - Run `dart test test/nested/simple_test.dart --pause-after-load` and open
+DevTools to see the `package:dart_foo` extension connected to a Dart test.
+
+- Run `flutter test test/app_that_uses_foo_test.dart --start-paused` and open
+DevTools to see both the `package:foo` and `package:dart_foo` extensions
+connected to a Flutter test. -->
+
+## Learn how to structure your Dart package
+
+The examples will show you how to structure your package for optimal extension
+development and publishing.
+
+1. If you are adding a DevTools extension to an existing Dart package, this is
+the recommended structure:
     ```
     foo/  # formerly the repository root of your pub package
         packages/
@@ -20,27 +80,60 @@
             extension/
                 devtools/
                 build/
-                    ...  # pre-compiled output of foo_devtools_extension
+                    ...  # pre-compiled build output of foo_devtools_extension
                 config.yaml
             foo_devtools_extension/  # source code for your extension
     ```
-2. Configure your extension using the `foo/extension/devtools/config.yaml` file
-    ```yaml
-    name: foo
-    issueTracker: <link_to_your_issue_tracker.com>
-    version: 0.0.1
-    materialIconCodePoint: '0xe0b1'
+    `package:foo` and `package:dart_foo` provide an example of this structure.
+
+2. If you are creating a DevTools extension as a standalone package, this is
+the recommended structure:
     ```
-3. Use `package:devtools_extensions` and `package:devtools_app_shared` to
-develop your DevTools extension (see source code under `foo_devtools_extension`).
-4. Ship your extension with your pub package by including the pre-built assets
-in the `foo/extension/devtools/build` directory.
-    - For this example, the pre-built assets for `foo_devtools_extension` were added
-    to `foo/extension/devtools/build` by running the following command from the
-    `foo_devtools_extension/` directory:
-        ```sh
-        flutter pub get &&
-        dart run devtools_extensions build_and_copy \
-            --source=. \
-            --dest=../foo/extension/devtools 
-        ```
+    standalone_tool/ # your new pub package
+        extension/
+            devtools/
+            build/
+                ...  # pre-compiled build output of standalone_tool
+            config.yaml
+        lib/  # source code for your extension
+    ```
+    <!-- TODO(kenz): uncomment once these examples are provided. -->
+    <!-- `package:standalone_tool` and `package:gemini_ai_tool` provide an example of this structure. -->
+
+The pre-compiled build output included in the example packages'
+`extension/devtools/build` directories were included using the `build_and_copy`
+command provided by `package:devtools_extensions`.
+  - For example, `package:foo`'s `extension/devtools/build` directory was populated
+  by running the following command from the `foo_devtools_extension/` directory:
+
+    ```sh
+    flutter pub get &&
+    dart run devtools_extensions build_and_copy \
+        --source=. \
+        --dest=../foo/extension/devtools 
+    ```
+## Learn how to configure your extension's `config.yaml` file
+
+In these examples, you will also learn how to properly configure your extension's
+`config.yaml` file. DevTools reads this file in order to embed your extension in its
+own tab. This file must be configured as shown. 
+
+```yaml
+name: foo
+issueTracker: <link_to_your_issue_tracker.com>
+version: 0.0.1
+materialIconCodePoint: '0xe0b1'
+```
+
+For the most up-to-date documentation on the `config.yaml` spec, see
+[extension_config_spec.md](https://github.com/flutter/devtools/blob/master/packages/devtools_extensions/extension_config_spec.md)
+
+## Learn how to use shared packages from DevTools
+
+To learn how to use the shared packages from Devtools (`package:devtools_extensions`
+and `package:devtools_app_shared`), see the source for the `package:foo` extension.
+
+`packages_with_extensions/foo/packages/foo_devtools_extension` provides in-depth
+examples of how to do things like interact with the connected app's VM service,
+read / write to the user's project files over the Dart Tooling Daemon, interact
+with the DevTools extension framework APIs, etc.

diff --git a/packages/devtools_extensions/example/app_that_uses_foo/lib/main.dart b/packages/devtools_extensions/example/app_that_uses_foo/lib/main.dart
index a5bc3cb..5b10845 100644
--- a/packages/devtools_extensions/example/app_that_uses_foo/lib/main.dart
+++ b/packages/devtools_extensions/example/app_that_uses_foo/lib/main.dart

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:dart_foo/dart_foo.dart';
 import 'package:flutter/material.dart';
 import 'package:foo/foo.dart';
 
@@ -36,11 +37,13 @@
 
 class _HomePageState extends State<HomePage> {
   late final FooController fooController;
+  late final dartFoo = DartFoo();
 
   @override
   void initState() {
     super.initState();
     fooController = FooController.instance;
+    dartFoo.foo();
   }
 
   @override

diff --git a/packages/devtools_extensions/example/app_that_uses_foo/test/dart_test/example_dart_test.dart b/packages/devtools_extensions/example/app_that_uses_foo/test/nested/simple_test.dart
similarity index 100%
rename from packages/devtools_extensions/example/app_that_uses_foo/test/dart_test/example_dart_test.dart
rename to packages/devtools_extensions/example/app_that_uses_foo/test/nested/simple_test.dart


diff --git a/packages/devtools_shared/test/server/server_api_test.dart b/packages/devtools_shared/test/server/server_api_test.dart
index 16c1faf..348cf4b 100644
--- a/packages/devtools_shared/test/server/server_api_test.dart
+++ b/packages/devtools_shared/test/server/server_api_test.dart

@@ -35,7 +35,7 @@
       request,
       extensionsManager: ExtensionsManager(buildDir: '/'),
       deeplinkManager: fakeManager,
-      analytics: NoOpAnalytics(),
+      analytics: const NoOpAnalytics(),
     );
     expect(response.statusCode, HttpStatus.ok);
     expect(await response.readAsString(), '["debug", "release]');
@@ -57,7 +57,7 @@
         request,
         extensionsManager: ExtensionsManager(buildDir: '/'),
         deeplinkManager: FakeDeeplinkManager(),
-        analytics: NoOpAnalytics(),
+        analytics: const NoOpAnalytics(),
       );
       expect(response.statusCode, HttpStatus.badRequest);
     },
@@ -87,7 +87,7 @@
       request,
       extensionsManager: ExtensionsManager(buildDir: '/'),
       deeplinkManager: fakeManager,
-      analytics: NoOpAnalytics(),
+      analytics: const NoOpAnalytics(),
     );
     expect(response.statusCode, HttpStatus.ok);
     expect(await response.readAsString(), someMessage);
@@ -117,7 +117,7 @@
       request,
       extensionsManager: ExtensionsManager(buildDir: '/'),
       deeplinkManager: fakeManager,
-      analytics: NoOpAnalytics(),
+      analytics: const NoOpAnalytics(),
     );
     expect(response.statusCode, HttpStatus.ok);
     expect(await response.readAsString(), someMessage);
@@ -150,7 +150,7 @@
       request,
       extensionsManager: ExtensionsManager(buildDir: '/'),
       deeplinkManager: fakeManager,
-      analytics: NoOpAnalytics(),
+      analytics: const NoOpAnalytics(),
     );
     expect(response.statusCode, HttpStatus.ok);
     expect(await response.readAsString(), someMessage);
@@ -174,7 +174,7 @@
       extensionsManager: ExtensionsManager(buildDir: '/'),
       deeplinkManager: fakeManager,
       dtdUri: dtdUri,
-      analytics: NoOpAnalytics(),
+      analytics: const NoOpAnalytics(),
     );
     expect(response.statusCode, HttpStatus.ok);
     expect(