Wall it in and make a nice pantry with a wine refrigerator.

Interesting idea.

That cut out looks awkward from this angle, what is it like from the other side? I would think fill it in and add cabinets and a wine fridge like Jacqui said.

Here’s a pic

My concern would be that the mudroom and hallway won’t have any natural light.

Which walls are supporting?

Good question. I don’t know. I’d have to talk to the builder.

You could use it for a small appliance space. Coffee maker, toaster, blender, food processor, stand mixer, etc.

Yup, equally awkward from the other side. Go buy a gorgeous pendant and some under cabinet lights. You won’t miss the light from the pass through.