On a HomeRunner site that uses Stripe for payments, the GA4 purchase event does not come from Stripe. Stripe’s role is limited to card validation during checkout.
How the event is sent. After checkout, your guest lands on your site’s own confirmation page (/confirmation/ with the reservation ID in the URL). The HomeRunner plugin loads that reservation from the booking engine and emits a GA4 purchase event containing transaction_id, value, currency, tax, and line items (the stay, taxes, and each fee).
When it fires. The event fires only when the booking engine reports the reservation as confirmed. Failed or abandoned payments never reach a confirmed reservation, so they do not produce a purchase event. Unconfirmed inquiry-style bookings emit generate_lead instead.