I have this container which probably at one time held an expensive bottle of
port. I would like to know what type of plywood it is and where I could get
some.

The first picture shows the container closed. The second shows it open. The
plywood is very flexible. It is 1.27mm (0.05") thick. It is three plies.
The outer plies are about 0.2 or 0.3mm, so the inner ply is about 0.6mm.
The third picture attempts to show what the plywood looks like edge-on.

I would like to know what the plywood is called and where to obtain it.

Cheers,

Larry