### Packaging: objects, the stage index, the floor, catalogs and the package receipt

- **Objects** ([packaging](extensions/packaging.md) §5): each one envelope, named by its
  receipt content hash, with no manifest member naming a position, so a repeated piece
  is one object. The packer's base encode calls `choose_q` per piece.
- **The stage index** `WSIX` (§6, `wai-rs` `stage_index`, feature `video_package`): per
  component, every object of the package by content hash, its lengths, role, layer,
  the tier and decoded-output digest of the prefix it completes, its SSE, and the class
  plan; its digest and a Merkle stage root; a named reason for every rule a verifier
  applies to an index and to the objects it lists.
- **The floor** (§7): a supplied AV1 floor, checked against the keyframe plan
  (`wai-pack plan --out`) and the listing the policy pins, written as floor objects
  that carry `derived_from` and as CMAF files (`init.mp4` with `av01`/`av1C`, one
  fragment per piece).
- **SPEC §7.1, *Derived renditions***: `derived_from` on a manifest or a rendition
  entry states that a payload presents another object and was made from it; an
  OPTIONAL member under the MINOR rule that never breaks a parse (§8).
- **Catalogs** (§8): on http-delivery's Mode N, a classical master and floor playlist
  that name nothing of WAI; per class, its master (with the one SESSION-DATA line
  http-delivery allows), its WAI playlist with the codecs union and floor, and a WAI
  media playlist adjacent to the floor's, with `#EXT-X-GAP` for a piece the class
  takes as floor only and a `#WAI-LAYER` line for each refinement layer it lists (no
  package of this revision carries one: the packer refuses refinement rungs, §11.4);
  the classical and per-class DASH MPDs; the MoQ catalog; and a stage view per class.
- **The version-2 package receipt** (§9, `wai-rs` `package`): binds the policy digest
  and each component's index by digest and stage root, with entry, object and byte
  counts every verifier recomputes; RFC 8785 JSON both ways; a measurement claim beside
  a metered figure. The version-1 receipt gains the same JSON form and keeps its
  bytes. Both share the figure profile `wai:video-package-receipt-id`.
- **`wai-pack pack`, `verify` and `listing`**, and the corpus's golden package
  `video-base-01`, its index, object and receipt mutations with their reasons, and
  version-1 receipts as JSON. The registry lists packaging's wire identifiers.
- No envelope byte or receipt byte changes for existing material.

