I would assume paper like they used to put in old Chinese lanterns.
Nonetheless...it is fragile and should be framed in a shadow box.Any good local framing store could do it for you.
If I owned it,that's what I would do asap. I am a procrastinator,that's why I suggest doing it now. Plus...you do not want any more damage done to it and if it lays around too long,that just might happen.
When you get sick of it let me know ok?