Wouldn't there have to be historical matches to train on? Tons of chess games out there but doubt there are any connect 4 games. Is there even official notation

Wouldn't there have to be historical matches to train on? Tons of chess games out there but doubt there are any connect 4 games. Is there even official notation for that? My assumption is that chatgpt can play chess because it has studied the games rather than just reading the rules.