> It is missing the Italian, Japanese, Greek and Mexican cooking - that are incredibly popular worldwide and it is incomplete without them, and nothing from Africa at all or Middle East.

That's overstating it. There are certainly English-language sources describing Italian, Japanese, Greek, Mexican, African, and Middle Eastern recipes. They're likely not the most authoritative sources, but it's not as if I'd expect these cuisines to be completely absent.

The actual corpuses they used are listed in the supplement: https://arxiv.org/src/2605.22391v1/anc/supplement.pdf

edit: that document also breaks it out by region, including 33,923 Japanese recipes which seems respectable. 324 from Sub_Saharan_African which is tiny but still more than 0. Italian and Greek are likely a fair chunk of Mediterranean (164,107). I don't see a breakout for Middle Eastern. Some might be lumped into Mediterranean as well.