docs: add examples of Jupyter Server extensions

Author: oliver-sanders

docs/source/developers/extensions.rst

@@ -6,9 +6,13 @@ Server Extensions
 
 A Jupyter Server extension is typically a module or package that extends to Server’s REST API/endpoints—i.e. adds extra request handlers to Server’s Tornado Web Application.
 
-You can check some simple examples on the `examples folder
+For examples of jupyter server extensions, see the
+:ref:`homepage <examples of jupyter server extensions>`.
+
+To get started writing your own extension, see the simple examples in the `examples folder
 <https://github.com/jupyter/jupyter_server/tree/main/examples/simple>`_ in the GitHub jupyter_server repository.
 
+
 Authoring a basic server extension
 ==================================
 

docs/source/index.rst

@@ -11,7 +11,8 @@ You've landed on the documentation pages for the **Jupyter Server** Project. Som
 Introduction
 ------------
 
-Jupyter Server is the backend—the core services, APIs, and `REST endpoints`_—to Jupyter web applications.
+Jupyter Server is the backend that provides the core services, APIs, and
+`REST endpoints`_ for Jupyter web applications.
 
 .. note::
 
@@ -21,6 +22,34 @@ Jupyter Server is the backend—the core services, APIs, and `REST endpoints`_
 .. _Jupyter Notebook: https://github.com/jupyter/notebook
 .. _REST endpoints: https://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyter/jupyter_server/main/jupyter_server/services/api/api.yaml
 
+
+Applications
+------------
+
+Jupyter Server extensions can use the framework and services provided by
+Jupyter Server to create applications and services.
+
+Examples of Jupyter Server extensions include:
+
+.. _examples of jupyter server extensions:
+
+`Jupyter Lab <https://jupyterlab.readthedocs.io>`_
+   JupyterLab computational environment.
+`Jupyter Resource Usage <https://github.com/jupyter-server/jupyter-resource-usage>`_
+   Jupyter Notebook Extension for monitoring your own resource usage.
+`Jupyter Scheduler <https://jupyter-scheduler.readthedocs.io>`_
+   Run Jupyter notebooks as jobs.
+`jupyter-collaboration <https://jupyterlab-realtime-collaboration.readthedocs.io>`_
+   A Jupyter Server Extension Providing Support for Y Documents.
+`NbClassic <https://jupyterlab.readthedocs.io>`_
+   Jupyter notebook as a Jupyter Server extension.
+`Cylc UI Server <https://cylc.org>`_
+   A Jupyter Server extension that serves the cylc-ui web application for
+   monitoring and controlling Cylc workflows.
+
+For more information on extensions, see :ref:`extensions`.
+
+
 Who's this for?
 ---------------
 
@@ -33,6 +62,7 @@ The Jupyter Server is a highly technical piece of the Jupyter Stack, so we've se
 
 If you finds gaps in our documentation, please open an issue (or better, a pull request) on the Jupyter Server `Github repo <https://github.com/jupyter/jupyter_server>`_.
 
+
 Table of Contents
 -----------------