On the GitHub dashboard you find a new section called Favorites on top ob the left sidebar. Here you will find all your saved repositiories.
Go to the detail page of you repository. On the top right you find a new button called Favorites (it should be green)
. Click the button and you repository has been saved to your list.
Go to the detail page of you repository. On the top right you find a new button called Favorites (it should be red)
. Click the button and you repository has been deleted from your list.