Trashbin is a special type of folder where all deleted episodes are kept, when it is enabled.
Trashbin is specifically used to kept unnecessary episodes for a while and get ride of them at once when you are sure that you don't need them any more. You can also think of it as a second chance to rescue accidentally deleted episodes. Episode inside the trashbin is called trashed item and stays inside till you clean the trashbin.
Trashbin comes in disabled mode.