Brand according to documents: SMEG.
Most similar models I an find: https://www.smeguk.com/products/UKC8173N1F and https://www.smeguk.com/products/UKC81721F, the keyword are "built-in" and "integrated", other very similar ones: https://www.smeguk.com/refrigerators/built-in
Looks like this: https://www.youtube.com/watch?v=4c_LBVnU4ec and that's how to unclog the drain.
2020-11-28: defrost. Some small Styrofoam was broken lose from top, noticed small burn or rust marks on top grid nearby.