I went to the corner shop yesterday evening for some more laban, and found a carton of "raïb" by Luxlait.
I just tried it: it's more like a very wet cottage cheese; there are distinct chunks, but they are very, very soft. It's slightly more acid than the Luxlait laban, and is also 2.5% fat, compared to 1.5% for the laban.
I've been trying to compose the word "raïb" in Arabic, to try to find more information about it, but can't manage to get what I think is the third letter. From right to left, I see "reh", "alef", then something unidentifiable, then "beh".
ETA: I found
an article on how to make the stuff at home, and that article uses the word "رايب", so by searching in a Unicode character utility, I found "reh", "alef", "yeh" and "beh"; yeh on its own looks different, "ي" which is why I didn't recognise it.
The article is in French and Arabic; it looks like you need to start with a live yoghurt and some milk, and leave the two together to work overnight.