- You're allowed to make mods based on these assets, even if paid. Vault/private them as much as you want, yes. - You can use included meshes and textures for your artwork/render, as long as you don't claim these assets to be your own. - You are NOT allowed to port any part of the mod into other games/applications. The Dev Kit can be ported to work in other programs (e.g. Blender, Maya). - Credit where it's due.