This class is meant to be used with your Github hosted WordPress plugins. The purpose of the class is to allow your WordPress plugin to be updated whenever you push out a new version of your plugin; similarly to the experience users know and love with the WordPress.org plugin repository.
When I delpoy a new update the Wordpress system detects it and shows the update Icon in Admin bar as expected, but
wp-admin/update-core.php
showsPlugins Your plugins are all up to date
WP Version 3.6.1