Prefix is the key prefix within that bucket holding EXACTLY this deployment's objects — the unit an upload grant is scoped to, so a grant for one deployment cannot write over another.
Status is where the attempt got to — queued, live, or failed. A deployment that is live is not necessarily the one SERVING: the project's own currentDeploymentId says which is.
Upload is the prefix-scoped, short-lived S3 write grant handed to CI with a queued git deployment, so it needs no bucket credential (grant.go). Present ONLY on the 202 that creates the deployment — it is never stored and never replayed on a later read, so a grant cannot outlive the build it was minted for by being fetched again.
Version counts deployments of this project from 1, so the history reads as an ordered sequence rather than by timestamp. It is per project, not global.