x-apisjson-source
`x-apisjson-source` appears in the info block. Its value is a string. Used by 9 providers across 9 OpenAPI documents. Observed values include `https://partner.calm.com/docs/api`, `postman/homeward-offer-estimate-postman.json`, `https://apidocs.persistiq.com/`, `https://developer.rockbot.com/api.html`. Consistent with provenance — this is inferred from where the key appears and what it carries, not from any published definition.
Where it appears
| Location in the document | Occurrences | |
|---|---|---|
| info | 9 |
What its value looks like
| Value shape | Occurrences |
|---|---|
| string | 8 |
| object | 1 |
Observed values
Sampled from the specifications, most frequent first.
Providers publishing it
All 9.
Why this is not in OpenAPI
Extensions exist because a provider needed something the specification would not carry. Most of what they hold is not the API contract at all — it is operational metadata about the contract: documentation, lifecycle, policy, provenance, and now agents. That metadata is usually better placed alongside the contract, in an Overlay or an APIs.json index, than crammed inside it. See everything else doing the provenance job.