Default options.txt file generation
You can ship default options from options.txt with KubeJS. This includes keybindings, video settings, enabled resource packs, controls like autojump and toggle sprint and wierd things like advanced tooltips.
Why use this instead of just shipping options.txt? If you ship options.txt then the users options will get overridden every time they update your modpack, where-as KubeJS only sets the options once, on the first time the modpack boots.
To use it simply make a file called
kubejs/configfolder. Then copy any lines you want to set by default over from the normal options.txt file. You can also just copy the entire file if you want to include everything.
A full list of what options the options.txt file can contain is available on the Minecraft Wiki.