What is the /.well-known/api-catalog file?
We request /.well-known/api-catalog and record the status; anything other than 200 is a Warning.
What it is
RFC 9727 defines a single well-known address where a domain lists the APIs it publishes. The catalogue is a linkset pointing at each API's description document.
It answers a question an agent otherwise cannot: does this organisation have a machine interface, or is HTML the only way in.
This Check records the status of that one request. We do not parse the linkset, so a 200 is as far as the Evidence goes.
Why an agent needs it
An agent that can call your API does not have to read your pages, fill your forms or guess your prices. It is the shortest path between a buyer's intent and your system.
Absent is a Warning, not a Fail. Most sites have no public API, and a catalogue listing nothing would be worse than none.
The Fix
If you have a public API, publish a catalogue at /.well-known/api-catalog as a linkset, following RFC 9727. Point each entry at the OpenAPI document that describes the API.
Keep the descriptions current with the API itself. A catalogue that lists a retired endpoint sends an agent to a 404 with your name on it.
If you have no public API, this stays a Warning and costs you little. Spend the effort on the Checks marked High priority first.
This one is a change in your own markup or edge configuration, so the Fix Pack cannot write it for you. A Report names every page it affects, with the Evidence.