options for [slider] shortcode?

What are the options for the built-in [slider] shortcode?

(I mean [slider] as in the piece of shortcode to hide part of a post behind an expanding/collapsing header. It’s one of the buttons in the post editor. Not a tool for showing a slideshow of images. For example:
[slider title=”This is a title”]Hello World[/slider]
)

These sliders by default start closed, but I would like to have them start open. Is there a property I can add to the shortcode to achieve this? Alternatively, can someone tell me where to find the actual code that the shortcode references? If I dig through that I should be able to figure it out.
(I couldn’t find any documentation in the codex about this piece of shortcode, or any mentions of it anywhere, really. All my searches here and on google only returned references to slider plugins for showing slideshows.)

thanks for your help