Issue 1:
I use the electron 9.0.0 and using the session API to load the react development tools,

the core code as follow:

app.on('ready', () => {
const reactExtension = path.join(os.homedir(), '/Library/Application Support/Google/Chrome/Default/Extensions/fmkadmapgofadopljbjfkapdkoienihi/4.7.0_0');
session.defaultSession.loadExtension(reactExtension).then(({ id }) => {
logger.debug(`load react extension ${id}`);
});
});

But it throw some warnings and the tool is not loaded:

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.

Issue 2:
Preflight Checklist

I have read the Contributing Guidelines for this project.

I agree to follow the Code of Conduct that this project adheres to.

I have searched the issue tracker for an issue that matches the one I want to file, without success.

Issue Details

Electron Version:

v9.0.0

Operating System:

macOS 10.15.4

Last Known Working Electron version:

8.2.0

Expected Behavior

In our project we are loading ReactDevTool and ReduxDevTools.

app.on('ready', async () => {
await session.defaultSession.loadExtension(
path_to_devtools
);
});

In the terminal for version 9.0.0 we see warnings:

(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.

And both extensions don't work.

Actual Behavior

No warnings in the terminal and working extensions.