I really want to get this assets packs for rpg maker and I already made the same question, sadly the creator never replied and he/she said and I quote: "I'm also working with all these tileset together for Rpgmaker and Godot compatibility, which will be the upcoming update in the next weeks!"
That was half a year ago, so my guess is that sadly this is just an abandoned asset pack with no future content planed. Sad for everyone that got the packs hoping for RPG maker support.