/v1/…). The
X-API-Version header is optional, but when you send it, it must name the
same version — 1 or v1 for a /v1/ path.
Not retryable. Remove the header or make it agree with the path.
All error codes and the retry model: Errors.version_mismatch
HTTP 400 — the X-API-Version header does not match the version in the path.
The API version is carried in the path prefix (