Haven't found it anywhere yet.
It is intentionally not publicly available.
I'm working a bit on the tail with cardboard and cad and knowing how the charging setup will be would help a lot with designing before it arrives.
Plan for a set of high capacity power cables much like the ones that run from the battery to the controller B+/B- terminals, but capped with a red Anderson connector. That is literally what we're talking about. I can't discuss lengths or such, but I will say that routing high power cables should be done with care to avoid motion, chafing, or excessive bending.
If you plan to put the supercharger on the tail rack, I highly recommend figuring out a way to reinforce the tail rack so that it cannot wave around at speed if going over a bump. (Terry welded tubes that run from the passenger footpeg area to the top plate, for example.) The stock rack is not suitable for loads of that size, in my opinion.