CS scripts packaged in a VAR are not automatically recognised, I didn't know that before.
Now it is fixed. The MMDShowcase.cs inside the package can be loaded correctly.
This script is important. It implements interface hiding, FOV reset, and the ability to touch the ball in front of you in VR mode to turn the menu into a pyrotechnic ball attached to your hand (touching the pyrotechnic ball reproduces the display menu).