How is this allowed on the Internet Archive? It was only published in the 90s, it is still under copyright. I thought the Internet Archive's publicly accessible book collection was supposed to only include content in the public domain (or otherwise freely licensed).

IA began to put up out-of-print items some time ago (old LPs for example). I'd guess that many books still under technical copyright can only be reprinted in small quantities (probably at a loss) and be hard to find. Seems a reasonable 'gentleman's agreement' that's working out for IA.

I can't find the Oware reference, and the game is not in the index.

it goes by other names as it's played widely across Africa. He may have used another name for it.