### Registrations: JPEG XS, MV-HEVC and a projection descriptor, IEEE 1857.11 as a candidate; header probes; CMSD reading; LOC carriage

- **New capabilities** (SPEC §5; the registry export). `wai.image.jxs` and `wai.video.jxs`, JPEG
  XS (ISO/IEC 21122): one codestream, or codestreams one a frame in `wai.video.av1`'s framing;
  `patent-pool`; `standard-defined`, because a sink that advertises either decodes at ISO/IEC
  21122-4's strict conformance point (Annex B.2: decoded images bitwise identical to the
  reference), which the registration requires. `wai.video.mvhevc`, MV-HEVC (ITU-T H.265 Annexes F
  and G): the Annex B byte stream of a multiview bitstream, `wai.video.hevc` its usable fallback;
  `patent-pool`; `standard-defined` on H.265 (V11) §F.13.5.1. `wai.meta.projection`
  ([projection](extensions/projection.md)): a companion descriptor, `WPJ1`, 40 bytes, saying how a
  video rendition's pictures map onto what a viewer sees (rectilinear, equirectangular,
  half-equirectangular, fisheye; angles in 2⁻¹⁶ degrees as ITU-T H.274 §8.15 states them) and how
  its two views are arranged (packed side by side or top and bottom as ITU-T H.273 §8.4 names
  them, or in two layers of a multiview bitstream); royalty-free. `wai.image.ieee1857_11`, IEEE
  1857.11-2024 neural-network-based image coding, registered as a **candidate**: the standard is
  not openly readable, and its open reference software writes a picture header with no start
  code, from a working draft; `NeuralFloat`.
- **Header probes** ([format-probes](extensions/format-probes.md)) for those capabilities and for
  `wai.video.hevc`, `wai.video.vvc`, `wai.video.lcevc`, `wai.audio.mpegh`, `wai.video.avs3` and
  `wai.audio.avs3`, which were registered with none: each identifies a payload as its
  capability's format and reads the parameters its headers state (profile, level, sizes,
  layers and views, sampling, configurations), or refuses it with a code of its §12. Each
  probe states its basis: the standard's own text (H.265, H.266), open implementations that
  agree where the standard is not openly readable (JPEG XS, LCEVC, MPEG-H, AVS3, IEEE 1857.11),
  or WAI's own format. For JPEG XS the probe gives the media-type parameters of RFC 9134 §7.1
  and states when a stream is the constant number of bytes a frame SMPTE ST 2110-22 carries.
  `wai-rs`: module `format_probe` (feature `format_probe`), tool `wai_format_probe`.
- **The corpus** [`format-probe-conformance/`](format-probe-conformance/): vectors written by
  permissively licensed encoders at pinned revisions from synthetic pictures (H.266, MV-HEVC
  with its base layer, JPEG XS image and video, AVS3), with the facts each encoder was asked
  for and every command and decode in `provenance.json`; generated vectors for LCEVC, MHAS, AVS3
  audio, the IEEE 1857.11 header and the projection descriptor; negative controls refused with
  every code; five LCEVC streams fetched by digest (`fetch.sh`); and `format_probe_verify.py`,
  written from the two extensions.
- **Measured for JPEG XS** (format-probes §3.6): the open decoder's C and SIMD paths give
  identical output on every JPEG XS vector; a second, independent decoder gives the same bytes on
  every vector whose profile it implements, and a lossless vector decodes to its source picture.
- **CMSD reading** ([delivery-telemetry](extensions/delivery-telemetry.md) §6.6): a reader of
  `CMSD-Static` and `CMSD-Dynamic` back into the descriptions §6.1 to §6.3 write, passing over
  other senders' keys, refusing with `cmsd_malformed`, `cmsd_type` or `cmsd_version`; the fields
  and outcomes in `telemetry-conformance/cmsd-read/`, and `cmsd_read_verify.py`. §10 lists the
  extension's CMCD and CMSD custom keys in full, and the registry lists each as a wire
  identifier of the new kind `telemetry-key`.
- **LOC carriage** ([loc-carriage](extensions/loc-carriage.md)): an envelope whose payload is one
  WebCodecs chunk (an Opus packet, an AVC or HEVC access unit, an ADTS frame) as one object of a
  track of packaging `loc` (`draft-ietf-moq-loc-04`), its manifest the Immutable Property
  `WAI_MANIFEST` and its receipt commitment `WAI_RECEIPT`, rebuilt by a reader byte for byte and
  checked against the receipt. The writer and reader are `joule-moq`'s `loc` module; the corpus
  is `live-conformance/loc/`, with `loc_verify.py`.

