https://wccftech.com/mario-tennis-aces-characters-bosses/

Warning: The following post may contain Mario Tennis Aces spoilers.

Last week Nintendo announced they’ll be holding a Mario Tennis Aces Pre-Launch Online Tournament (essentially a demo/beta test) and, in fact, you can download it via the Switch eShop right now. The tournament isn’t actually playable, as Nintendo hasn’t flipped on the servers yet, but some enterprising fans have already begun digging around in the demo’s code, and have uncovered some interesting tidbits.