diff --git a/Doc/library/idle.rst b/Doc/library/idle.rst
index 9e87704c286252..8249eeb15ccea9 100644
--- a/Doc/library/idle.rst
+++ b/Doc/library/idle.rst
@@ -37,6 +37,11 @@ IDLE has the following features:
 
 * configuration, browsers, and other dialogs
 
+The IDLE application is implemented in the :mod:`idlelib` package.
+
+This is an optional module. If it is missing from your copy of CPython, look for documentation from your distributor (that is, whoever provided Python to you).
+If you are the distributor, see Requirements for optional modules.
+
 Menus
 -----
 
diff --git a/Lib/idlelib/help.html b/Lib/idlelib/help.html
index fc618ab727d1fb..822ee99479c9dd 100644
--- a/Lib/idlelib/help.html
+++ b/Lib/idlelib/help.html
@@ -16,6 +16,9 @@
 of global and local namespaces</p></li>
 <li><p>configuration, browsers, and other dialogs</p></li>
 </ul>
+<p>The IDLE application is implemented in the <a class="reference internal" href="#module-idlelib" title="idlelib: Implementation package for the IDLE shell/editor."><code class="xref py py-mod docutils literal notranslate"><span class="pre">idlelib</span></code></a> package.</p>
+<p>This is an optional module. If it is missing from your copy of CPython, look for documentation from your distributor (that is, whoever provided Python to you).
+If you are the distributor, see Requirements for optional modules.</p>
 <section id="menus">
 <h2>Menus<a class="headerlink" href="#menus" title="Link to this heading">¶</a></h2>
 <p>IDLE has two main window types, the Shell window and the Editor window.  It is
@@ -516,7 +519,7 @@ <h2>Startup and Code Execution<a class="headerlink" href="#startup-and-code-exec
 executed in the Tk namespace, so this file is not useful for importing
 functions to be used from IDLE’s Python shell.</p>
 <section id="command-line-usage">
-<h3>Command line usage<a class="headerlink" href="#command-line-usage" title="Link to this heading">¶</a></h3>
+<span id="idlelib-cli"></span><h3>Command-line usage<a class="headerlink" href="#command-line-usage" title="Link to this heading">¶</a></h3>
 <p>IDLE can be invoked from the command line with various options. The general syntax is:</p>
 <div class="highlight-bash notranslate"><div class="highlight"><pre><span></span>python<span class="w"> </span>-m<span class="w"> </span>idlelib<span class="w"> </span><span class="o">[</span>options<span class="o">]</span><span class="w"> </span><span class="o">[</span>file<span class="w"> </span>...<span class="o">]</span>
 </pre></div>