Lightning Extension is a library of features created by the Lightning Product Management team at Salesforce. This extension is designed to complement the user experience with continuous productivity feature releases. These features provide end users with rich enhancements that aren’t available out-of-the-box with Lightning, like Dark Mode.
Admins can control which features are made available to their users. To control access to features, from Setup, in the Quick Find box, enter Lightning Extension, and then select Lightning Extension. From there, you can change your users’ access to individual features, or access to the extension itself. Changes can take up to 24 hours to take effect.
Note: Dark mode is temporarily disabled. We’re working to make it available again.