Install KSP mods properly.
The zip files posted to curseforge have always been for manual installation, and therefore no community standard exists for their directory structure. Auto-installation must follow suit in discovering the zip root's relationship with the target "Kerbal Space Program/GameData/" folder.
Joshua Lloyd commented
This. Twitch should attempt to find a GameData directory. Failing this it should assume the contents are direct drop to GameData. The *.version file is quite popular it would seem though, perhaps a key could be provided for the root path.