Delivery types
DELIVERY_TYPES in lib/domains/products/delivery.ts.
Embed / checkout theme
data-markt-theme, Markt.open({ theme }), and ?theme= on checkout URLs.
Custom domain status
Product visibility (storefront)
Products expose avisibility string on the public catalog. Values that block purchase include on-hold style holds enforced in embed/checkout start — private / on-hold products are rejected server-side.
Stock sentinel
Public catalogstock: -1 means unlimited (typical for non license-key delivery). License-key stock is a non-negative count of unused keys.