Restricted Site Notifier
by Fidgety Lizard on WordPress.org
Add-on for Restricted Site Access plugin. Displays site's current restriction status in the admin bar.

Admin bar showing status when site access is restricted
The Restricted Site Access plugin allows you to restrict a whole WordPress site to be visible only to logged-in users. This is very handy for development sites, and for providing members-only sites with no publicly-visible content.
This simple add-on plugin for Restricted Site Access adds a notification icon and message to the admin bar, showing the site’s current restriction status. This notification is only visible to admin-capable users, and means that an admin can always see the site’s current restriction status at a glance.
The plugin shows a locked padlock and a RESTRICTED status message if the Site Visibility setting has been restricted to logged-in or allowed-by-IP users.
It shows an unlocked padlock and an UNRESTRICTED status message for all other settings of Site Visibility.