feat(ietf): serve draft-20 FETCH within one group

doc/concept/standard.md

@@ -26,7 +26,7 @@ maps everything else to "not supported" or a harmless equivalent. The
 subset drops. What a peer actually observes against this implementation:
 
 - **Pull.** Subscribers ask. Single-track `PUBLISH` offers are declined; announce a namespace and serve the resulting subscriptions. Announcements go out unsolicited, and we also ask for every prefix we may discover. The solicit `SETUP` option makes us wait to be asked. Without it, a draft 16+ peer also gets each match as a `NAMESPACE` on its `SUBSCRIBE_NAMESPACE` stream, so it hears the namespace twice. We never send `PUBLISH`: on drafts 16 and 17 a `SUBSCRIBE_NAMESPACE` asking only for `PUBLISH` is refused, one asking for both gets only `NAMESPACE`, and any other Subscribe Options value closes the session.
-- **History is one group.** On drafts 14 through 19 a `FETCH` returns one whole group from the cache, or the saved prefix of the group a new subscription just joined. A range of groups is refused, as is any `FETCH` on draft 20 and later. JavaScript publishing refuses every `FETCH`. Datagrams are never fetchable. A Rust reader that only fetches learns the track from `TRACK_STATUS` instead of subscribing, so a finished track stays fetchable; draft 17 still subscribes, since its `TRACK_STATUS` answer cannot say whether the track is timed.
+- **History is one group.** A `FETCH` returns one group from the cache, or on drafts 14 through 19 the saved prefix of the group a new subscription just joined. A range of groups is refused, as is a draft 20+ `LOCATION_FILTER` that ends at Largest Object rather than an absolute End Location. On draft 20 and later, `FETCH_OK`'s End Location is the requested end, capped at Largest Object: a range holding no objects gets an empty fetch stream, and only a start past Largest Object is refused, with `INVALID_RANGE`. A relay's copy with no upstream subscription can't know Largest Object short of the track's end, so it echoes the requested end instead. JavaScript publishing refuses every `FETCH`. Datagrams are never fetchable. A Rust reader that only fetches learns the track from `TRACK_STATUS` instead of subscribing, so a finished track stays fetchable; draft 17 still subscribes, since its `TRACK_STATUS` answer cannot say whether the track is timed.
 - **Timing.** A track whose `SUBSCRIBE_OK` declares no `TIMESCALE` is untimed, as is every track on drafts 14 through 16. A Rust reader that never subscribed takes the units from `TRACK_STATUS` on draft 18 and later.
 - **Strict SETUP and parameters.** Repeated unknown `SETUP` options, GREASE included, are accepted if well-formed; a repeated known option is rejected. On draft 17 and later, a `GROUP_ORDER` other than Ascending (1) or Descending (2) closes the session. Message parameters follow the negotiated draft's lists: drafts 14 and 15 ignore an unknown or misplaced parameter, draft 16 ignores one defined only for another message but closes the session on an unknown one, and draft 17 and later close it on both.
 - **One credential per session**, carried in `SETUP` and forwarded to the [auth server](/bin/relay/auth#the-contract) unverified. A token attached to an individual request is ignored. An alias reference or a second token closes the session.

quest/m1/README.md

@@ -53,7 +53,6 @@ were done or not worth their cost.
 - [Bump web-transport-iroh for the capsule close](/quest/m1/iroh-capsule-bump.md) - condition: moq-dev/web-transport#419 ships in a release, then moq's iroh HTTP/3 client reports a peer's close capsule
 - [SUBSCRIBE_DROP](/quest/m1/subscribe-drop.md) - every stream group in a lite subscription arrives or is dropped by name, and lite-07 drops its stream count for it
 - [lite-07 Live flag](/quest/m1/lite-live.md) - a separate `Live` field on lite-07 SUBSCRIBE, so merged floors never starve a subscriber; late lower groups build on it
-- [Draft-20 FETCH](/quest/m1/ietf-fetch-location.md) - a draft-20+ FETCH within one group is served from its LOCATION_FILTER, as older drafts are
 - [FETCH_OK properties](/quest/m1/fetch-ok-properties.md) - our FETCH_OK carries the track properties SUBSCRIBE_OK does, as draft 16+ requires
 - [Subscribe ranges](/quest/m1/subscribe-ranges/README.md) - a lite-07 SUBSCRIBE asks for past and live ranges in either order and replaces FETCH; relays fill misses by range, including over moq-transport
 - [Cross-relay bursts re-run](/quest/m1/cross-relay-bursts.md) - condition: the #4349 reporter re-runs their A/B/C comparison against current cdn.moq.pro

quest/m1/fetch-ok-properties.md

@@ -32,9 +32,7 @@ opts out with INCLUDE_PROPERTIES = 0. Other fetch-only readers still need it.
   subscriber takes the units only from SUBSCRIBE_OK, and a fetch-only reader
   is untimed. Rejected: omitting timescale from FETCH_OK and leaving
   fetch-only readers untimed.
-- Honour INCLUDE_PROPERTIES (0x35) on FETCH from draft 20, once
-  [Draft-20 FETCH](/quest/m1/ietf-fetch-location.md) serves draft-20 FETCH at
-  all (today our publisher refuses every one). It defaults to sending the
+- Honour INCLUDE_PROPERTIES (0x35) on FETCH from draft 20. It defaults to sending the
   properties; at 0 the block is present but empty. `fetch.rs` decodes it into
   `Fetch::properties_wanted`, which the publisher does not honour yet.
 - Test per draft range: FETCH_OK round-trips the properties SUBSCRIBE_OK would
@@ -46,8 +44,3 @@ change how a fetch-only reader learns the track's properties.
 
 Public API: none. Wire: FETCH_OK gains its properties on drafts that define
 the block. Interop: run `just test interop --all`.
-
-## Required
-
-- [Draft-20 FETCH](/quest/m1/ietf-fetch-location.md) - draft-20 FETCH is served at all, and edits the same `run_fetch_stream`
-

quest/m1/subscribe-ranges/ietf.md

@@ -21,10 +21,10 @@ SUBSCRIBE, as open #4974 does for fetch-only demand.
 Serving downstream lifts the one-group refusal ("FETCH spanning several
 groups not supported") in `run_fetch_stream`
 (`rs/moq-net/src/ietf/publisher.rs`) for every draft, including draft-20's
-`FetchType::Filtered` once [Draft-20 FETCH](/quest/m1/ietf-fetch-location.md)
-serves it.
+`FetchType::Filtered`. Capping at the Largest Object also lifts the draft-20
+refusal of a filter bounded by it ("FETCH relative to Largest Object not
+supported"): no filter, a relative start, or an absolute start with no end.
 
 ## Required
 
 - [Model ranges](/quest/m1/subscribe-ranges/model.md) - the range requests this answers
-- [Draft-20 FETCH](/quest/m1/ietf-fetch-location.md) - serves draft-20 FETCH through the same group-span path this widens (#4971)