score:7
It turns out one can view their bus ticket on P-Airbus.com:
Enter the flight confirmation number along with the email used on Wizzair.com to reveal the E-ticket:
I think they're supposed to send out a notification 3 days before the flight takes place, but there's no need to wait for it. If the ticket doesn't show up on P-Airbus.com, it's possible to receive it by contacting the transfer service support at [email protected].