ActionView::Base::ObjectWrapper -- What's it for?

I've been going through the code and noticed this class as part of the
ActionView base.rb.

    class ObjectWrapper < #:nodoc:

As far as I can tell, it's just used in render_partial_collection when
calling render_partial, but the only thing that's done with it is
extract the value out of it again. As you can probably tell, I'm new to
Ruby programming (mostly Java bg), so maybe there's some magic that
happens by putting it into a struct, or maybe it's an extension point
that people can use. If the latter is the case, would someone be able
to provide an example of how it might be used?

Appreciate any help,

John Devine