The news collection is presented last and Pine knows not to save messages there. This is the default collection for your saved and sent messages folders. There is no limit to the number of collections you can have. Everyone starts with just one collection and few people ever have more than a dozen or so. Otherwise, Pine will never create any directories.
Local folders follow the local naming rules.
Pine users have the option of using folders which are stored on some other computer. If, as in these examples, there is no remote access protocol specified, then IMAP is assumed.