Everything between today and a public launch with real payments. Items marked checked live are measured by the server every time this page loads, so they cannot be ticked and cannot claim done when they are not. The rest are ticked by an owner and remembered for every admin, with who and when.
The items and their checks are defined in src/services/Readiness.ts; hand ticks are stored in admin_checklist and every tick is in the audit log. Payments in detail: Stripe activation.