# Retention and Deprecation

Deprecation removes an object from ordinary selection; it does not delete bytes or history.
Supersession is an explicit reference on the lifecycle subject. Archive means no active deployment
and hidden normal selection while identities, hashes, plans, evaluation and audit remain queryable.

`RetentionPolicyRevision` is versioned and immutable. The default `standard-rollback` revision
retains the previous stable target for at least 30 days after commit. A retention record distinguishes
`ACTIVE`, `ROLLBACK_RETAINED`, `DEPRECATED`, `ARCHIVABLE` and `ARCHIVED`; legal hold and unexpired
rollback state block cleanup. Tests use controlled timestamps to evaluate expiry without waiting.

Physical removal is always a separate cleanup operation. Archiving metadata does not imply removing
model weights, and deleting one node-local location does not mark an artifact globally missing while
another verified location remains.

M13 captures a migration rollback snapshot before external switch and applies the plan's minimum
30-day retention. Active migrations and unexpired rollback snapshots are cleanup blockers; orphan
shadow targets become explicit later cleanup candidates and are never auto-deleted.