X-Vercel-Cache HTTP Header
One of the following values is accepted.
The cache was bypassed and so the response was served from an origin server.
The response was served from the edge.
The response was not found in the edge and thus fetched from an origin server.
The response was served from static storage.
A stale response was found in the edge but revalidated synchronously.
The response is stale (served from the edge).