<p dir="auto">I use the electron 9.0.0 and using the session API to load the react development tools,<br>
the core code as follow:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="app.on('ready', () =&gt; {
  const reactExtension = path.join(os.homedir(), '/Library/Application Support/Google/Chrome/Default/Extensions/fmkadmapgofadopljbjfkapdkoienihi/4.7.0_0');
  session.defaultSession.loadExtension(reactExtension).then(({ id }) =&gt; {
    logger.debug(`load react extension ${id}`);
  });
});"><pre class="notranslate"><code class="notranslate">app.on('ready', () =&gt; {
  const reactExtension = path.join(os.homedir(), '/Library/Application Support/Google/Chrome/Default/Extensions/fmkadmapgofadopljbjfkapdkoienihi/4.7.0_0');
  session.defaultSession.loadExtension(reactExtension).then(({ id }) =&gt; {
    logger.debug(`load react extension ${id}`);
  });
});
</code></pre></div>
<p dir="auto">But it throw some warnings and the tool is not loaded:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="load react extension fmkadmapgofadopljbjfkapdkoienihi
(node:18404) ExtensionLoadWarning: Warnings loading extension at /Users/xalc/Library/Application Support/Google/Chrome/Default/Extensions/fmkadmapgofadopljbjfkapdkoienihi/4.7.0_0: Unrecognized manifest key 'browser_action'. Unrecognized manifest key 'minimum_chrome_version'. Unrecognized manifest key 'update_url'. Cannot load extension with file or directory name _metadata. Filenames starting with &quot;_&quot; are reserved for use by the system. "><pre class="notranslate"><code class="notranslate">load react extension fmkadmapgofadopljbjfkapdkoienihi
(node:18404) ExtensionLoadWarning: Warnings loading extension at /Users/xalc/Library/Application Support/Google/Chrome/Default/Extensions/fmkadmapgofadopljbjfkapdkoienihi/4.7.0_0: Unrecognized manifest key 'browser_action'. Unrecognized manifest key 'minimum_chrome_version'. Unrecognized manifest key 'update_url'. Cannot load extension with file or directory name _metadata. Filenames starting with "_" are reserved for use by the system. 
</code></pre></div>
<h3 dir="auto">Preflight Checklist</h3>

<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have read the <a href="https://github.com/electron/electron/blob/master/CONTRIBUTING.md">Contributing Guidelines</a> for this project.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I agree to follow the <a href="https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md">Code of Conduct</a> that this project adheres to.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have searched the issue tracker for an issue that matches the one I want to file, without success.</li>
</ul>
<h3 dir="auto">Issue Details</h3>
<ul dir="auto">
<li><strong>Electron Version:</strong>
<ul dir="auto">
<li>v9.0.0</li>
</ul>
</li>
<li><strong>Operating System:</strong>
<ul dir="auto">
<li>macOS 10.15.4</li>
</ul>
</li>
<li><strong>Last Known Working Electron version:</strong>
<ul dir="auto">
<li>8.2.0</li>
</ul>
</li>
</ul>
<h3 dir="auto">Expected Behavior</h3>
<p dir="auto">In our project we are loading ReactDevTool and ReduxDevTools.</p>
<div class="highlight highlight-source-js notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="app.on('ready', async () =&gt; {
    await session.defaultSession.loadExtension(
        path_to_devtools
    );
});"><pre class="notranslate"><span class="pl-s1">app</span><span class="pl-kos">.</span><span class="pl-en">on</span><span class="pl-kos">(</span><span class="pl-s">'ready'</span><span class="pl-kos">,</span> <span class="pl-k">async</span> <span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-c1">=&gt;</span> <span class="pl-kos">{</span>
    <span class="pl-k">await</span> <span class="pl-s1">session</span><span class="pl-kos">.</span><span class="pl-c1">defaultSession</span><span class="pl-kos">.</span><span class="pl-en">loadExtension</span><span class="pl-kos">(</span>
        <span class="pl-s1">path_to_devtools</span>
    <span class="pl-kos">)</span><span class="pl-kos">;</span>
<span class="pl-kos">}</span><span class="pl-kos">)</span><span class="pl-kos">;</span></pre></div>
<p dir="auto">In the terminal for version 9.0.0 we see warnings:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="(node:59148) ExtensionLoadWarning: Warnings loading extension at path_to_ext: Unrecognized manifest key 'browser_action'. Unrecognized manifest key 'minimum_chrome_version'. Unrecognized manifest key 'update_url'. Cannot load extension with file or directory name _metadata. Filenames starting with &quot;_&quot; are reserved for use by the system.
(node:59148) ExtensionLoadWarning: Warnings loading extension at path_to_ext: Unrecognized manifest key 'browser_action'. Unrecognized manifest key 'minimum_chrome_version'. Unrecognized manifest key 'update_url'. Cannot load extension with file or directory name _metadata. Filenames starting with &quot;_&quot; are reserved for use by the system.
(node:59148) ExtensionLoadWarning: Warnings loading extension at path_to_ext: Unrecognized manifest key 'commands'. Unrecognized manifest key 'homepage_url'. Unrecognized manifest key 'page_action'. Unrecognized manifest key 'short_name'. Unrecognized manifest key 'update_url'. Permission 'notifications' is unknown or URL pattern is malformed. Permission 'contextMenus' is unknown or URL pattern is malformed. Permission 'tabs' is unknown or URL pattern is malformed. Cannot load extension with file or directory name _metadata. Filenames starting with &quot;_&quot; are reserved for use by the system.
(node:59148) ExtensionLoadWarning: Warnings loading extension at path_to_ext: Unrecognized manifest key 'commands'. Unrecognized manifest key 'homepage_url'. Unrecognized manifest key 'page_action'. Unrecognized manifest key 'short_name'. Unrecognized manifest key 'update_url'. Permission 'notifications' is unknown or URL pattern is malformed. Permission 'contextMenus' is unknown or URL pattern is malformed. Permission 'tabs' is unknown or URL pattern is malformed. Cannot load extension with file or directory name _metadata. Filenames starting with &quot;_&quot; are reserved for use by the system."><pre class="notranslate"><code class="notranslate">(node:59148) ExtensionLoadWarning: Warnings loading extension at path_to_ext: Unrecognized manifest key 'browser_action'. Unrecognized manifest key 'minimum_chrome_version'. Unrecognized manifest key 'update_url'. Cannot load extension with file or directory name _metadata. Filenames starting with "_" are reserved for use by the system.
(node:59148) ExtensionLoadWarning: Warnings loading extension at path_to_ext: Unrecognized manifest key 'browser_action'. Unrecognized manifest key 'minimum_chrome_version'. Unrecognized manifest key 'update_url'. Cannot load extension with file or directory name _metadata. Filenames starting with "_" are reserved for use by the system.
(node:59148) ExtensionLoadWarning: Warnings loading extension at path_to_ext: Unrecognized manifest key 'commands'. Unrecognized manifest key 'homepage_url'. Unrecognized manifest key 'page_action'. Unrecognized manifest key 'short_name'. Unrecognized manifest key 'update_url'. Permission 'notifications' is unknown or URL pattern is malformed. Permission 'contextMenus' is unknown or URL pattern is malformed. Permission 'tabs' is unknown or URL pattern is malformed. Cannot load extension with file or directory name _metadata. Filenames starting with "_" are reserved for use by the system.
(node:59148) ExtensionLoadWarning: Warnings loading extension at path_to_ext: Unrecognized manifest key 'commands'. Unrecognized manifest key 'homepage_url'. Unrecognized manifest key 'page_action'. Unrecognized manifest key 'short_name'. Unrecognized manifest key 'update_url'. Permission 'notifications' is unknown or URL pattern is malformed. Permission 'contextMenus' is unknown or URL pattern is malformed. Permission 'tabs' is unknown or URL pattern is malformed. Cannot load extension with file or directory name _metadata. Filenames starting with "_" are reserved for use by the system.
</code></pre></div>
<p dir="auto">And both extensions don't work.</p>
<h3 dir="auto">Actual Behavior</h3>
<p dir="auto">No warnings in the terminal and working extensions.</p>