Looks like a typical Paiwan blade to me.
They say the "sheath needs a pillow to rest on, and so that's what the box is"...
The box does keep the main part of the sheath and blade off the surface though, so perhaps it helps keep the blade from lying in moist dirt and becoming rusted...
Also, SOMETIMEs that box is hollow, and can be a small compartment for storing something, like string, or flint, or a tiny carving blade, or a charm, or whatever...