Tnx to Carlb for pointing to the shorter Wikipedia at the .cx address. (CX is Christmas Island, an Australian territory not that far from Jakarta. That's exotic enough but then I went up to the homepage, which seems to be the Portuguese Wikipedia site.) With some effort I loaded the 15 files (total is 600MB) onto the 2MB SD card, using Calibre. Kobo accepted them, after some hiccuping.
Wikipedia on the Kobo lacks search, of course, and getting to an individual article takes loading one of the volumes, then clicking in the TOC to see if your topic is there, but it does work. The format is best at smallest type size, but all the illustrations in the files seem intact.
I hope the next firmware will facilitate using such reference works on the Kobo, ideally with ability to have at least two books open at the same time.