Download the kit again
For a new computer, a lost zip or a new version. Use the email you paid with and one thing from the purchase: the last four digits of the card, or the receipt number from the receipt email.
If neither works (a few payment methods carry no card digits), email jonathonwager@plaugstudios.com from the address you paid with and I'll send you a link.
Five tries an hour from one connection. What the check shares with Stripe is on the privacy page.