OK, seen the photos now, on page 10 of the original thread.
Yes, it looks like a simple domestic wallsafe about a foot square, set in concrete like mine. It looks from the frame round the door like it might be a floor safe, so it could be deeper than a typical wallsafe.
You could put your best jewellery in it, wads of cash, or, in Trumpville, a pistol. I presume it had a lift-off cover to prevent intruders easily seeing it.