Hidden, readable and writeable using local files. File core/lib/Drupal/Core/StreamWrapper/StreamWrapperInterface

public StreamWrapperInterface::getUri()

public static StreamWrapperInterface::getType()

Exposed in the UI and potentially web accessible. File core/lib/Drupal/Core/StreamWrapper/StreamWrapperInterface

Visible, readable and writeable using local files. File core/lib/Drupal/Core/StreamWrapper/StreamWrapperInterface

public StreamWrapperInterface::getName()

Defines the stream wrapper bit flag for a hidden file. This is not visible in the UI or accessible via web, but readable and writable; for instance

public StreamWrapperInterface::getExternalUrl()

Visible and read-only. File core/lib/Drupal/Core/StreamWrapper/StreamWrapperInterface.php, line 82

This is the default 'type' falg. This does not include StreamWrapperInterface::LOCAL, because PHP grants a greater trust level to local files (for example, they can be used