All game mechanisms come from the core game ; the Mods can only change the bounce physics.
You can get a sense a what cannot be changed by Mods by checking the official changelog here :
topic15-36309.php .
What was your goal with accessing old XKT versions ?
The XKT Modders asked me to hide your Mods ; IIRC correctly, you should still be able to update them on the website and get their update in-game, as long as you don't unsubscribe them. You can make them back to visible and hide them again once updated if required. Contact them if you want to organize that differently.
