OG, I'm confused. Your link indicates 'built under' but Baldric's says //Integrated or built-in fridges sit behind kitchen cupboard doors so they become a part of the kitchen itself.//
I thought 'built in' implied they were behind doors too, but I now assume I was mistaken, since I came across the link I posted that showed under was under worktop height; and 'built in' could be anything but presumably kept for those which can't go under the worktop.
It is possible 'built in' does mean behind closed doors but 'built under' implies under a worktop, and you need something that does both.
But it's just may take on what I found. End of day maybe ask the supplier you are thinking of purchasing from ?
Whichever you decide upon assure there's sufficient ventilation since if the appliance is too tightly confined the compressor works harder and the fridge isn't as effective. This can lead to premature failure...
Each make (at least here in the U.S. includes a manufacturer's minimum air clearance specifications in the Owner's Manual.