If you log out of a Drupal site and then hit the back button,
you can see pages from the authenticated user's previous session.
This could be a problem on public computers, if the authenticated user
had permission to see content protected by node access (or similar).
So the logout redirect module is designed to stop this behaviour.
So after user logging off if browser back button is clicked then this module is
redirecting user to default drupal login page or you can redirect that user to
custom login page which can be set by administrator from configuration form.
Configuration is simple. 'Configuration >> System >> Logout Redirect Configuration. Enter the URL you want to refer to if the back button of the browser is clicked after logging out
In this example we redirect to the login page /user/login.