When files or folders are deleted via the methods deletefile or deletefolder, then they actually are kept in the system, but they are not shown in the methods for working with files and folders and access to them is not provided.

They are moved to the Trash, from which they could be restored or removed.

If a entry from the Trash is restored, then it is placed back to the file system and the operations to it are again enabled, as it was not deleted.

If a entry from the Trash is removed, then the information about it is deleted from the database and after period of time the files that were related to this entry are also deleted.