Leak Pokémon Legends Z-A is fully playable from start to finish, PC Build Also Leaked

People keep saying it leaked without giving any substantial info on what the game is or how it plays. Could be true, but seems a bit off
 
Someone correct me if I’m wrong but the leakers said they aren’t going to leak any details about the game or future games, correct?
 
Don't most Nintendo games have a PC build for testing? Pretty sure that's been consistent since like, GameCube. Odd that people are surprised this exists