The "cheese physics" (lol) are all bevy_xpbd. The character controller is pretty rudimentary, it just adds a small force and roll-axis torque whenever the player holds left/right. So in the air you get a little motion and while rolling you "tilt" over. It's not the best but it seems to behave well enough.
Thanks for playing, and a hearty thank-you as well to your computer. I hope you had fun!