Obviously includes the existing two expansions (Marshal & Prisoners, and Horses & Stagecoach) (but not the Time Travel Car promo). The new bandit “Silk” will apparently be available for purchase later, and they’re talking about a new expansion “2 Trains, 1 Mission” next year. (Looks as if “Indians” has been permanently abandoned, probably for the best.)
Exploding Kittens has bought Happy Salmon from North Star Games, and will release a new edition later this year “with an Exploding Kittens twist”. So if you want a copy, probably buy it now.