Attaches to the back to the elite strap using zip ties. Does require support. Fairly simple to print.
Holds this power bank on the back of the quest 2:
https://www.amazon.com/gp/product/B08T8TDS8S?
I used this cable to connect the power bank to the quest 2:
https://www.amazon.com/gp/product/B01MZ8RA3A
The author hasn't provided the model origin yet.