[help] how to open a PAX file?

Hi!

A question : I would like to open a Keynote Theme under Windows.

I can unstuff it perfectly, but there is a main file with a ".pax" extension into the folder of the theme. Do you know how to open this PAX thing?

Googling makes me just a bit more confused about this.

Then thanks a lot if you can give me some tips and tricks!

All the best,

Don.