Move Cesium viewer, map, sky, projection, trail and sonar internals into
its engine. Drive styles, bloom, sharpening and contact sonar through
engine.render. Count camera-input suspensions across all three engines
and migrate the feature callers. Preserve Cesium's effects and input
behaviour; fix transit lens clicks on Cesium and make zero sharpening on
Navara disable sharpening, as it does on Cesium.
Parse imported files into plain records and draw them through movers,
lines, ground and imagery on both engines. Follow Cesium's KML style
precedence, preserve local KMZ images and frame the drawable records.
Open overlays use imagery when the engine has no native map-overlay API.
Run every imported-display case on fake and headless Cesium engines.
The shared import path retains these known differences from Cesium's old
DataSources: wall fills, extruded prisms and gx:LatLonQuad are undrawn;
raised polygon fills drape while outlines retain altitude; GroundOverlay
rotation, altitude and RGB tint are not applied; rhumb lines become great
circles. Ground heights use the loaded surface synchronously instead of
waiting for most-detailed sampling. Supported KMZ ground overlays now
draw on Navara too. Document the limits rather than claiming full parity.
Combine batches B and C because their disjoint path manifests cannot
place the shared boundary and format files in a later commit while
keeping B independently valid. This combined commit owns the shared
docs, package boundaries, format scope, locale catalogs and coupling
baseline. Remove five obsolete import strings from all eleven catalogs.
Make the load-time source scan include new files and skip deleted paths
so the same checks work before and after recording the moves.
Coupling: Navara renderer lines fall from 1695 to 1294, Cesium import
files from 25 to 9, viewer lines from 1177 to 1026, SDK loads from 4 to 3
and engine-name lines from 62 to 42. No count grows.
The full unit suite and the boundary, format and coupling checks pass.
Browser validation remains to be run.
Browser checks to run
GOOGLE_MAPS_API_KEY= CESIUM_ION_TOKEN= npm run dev -- --port 4291
node scripts/qa-contract-suite.mjs http://localhost:4291
node scripts/qa-navara-visual-styles.mjs http://localhost:4291
node scripts/qa-navara-bloom.mjs http://localhost:4291
node scripts/qa-navara-sonar.mjs http://localhost:4291
QA_BASE_URL=http://localhost:4291 node scripts/qa-visual-effects.mjs
QA_BASE_URL=http://localhost:4291 node scripts/qa-zoom-out-guard.mjs
node scripts/qa-sky-model-lighting.mjs --url http://localhost:4291
node scripts/qa-geo-import.mjs http://localhost:4291
node scripts/qa-geo-import-regressions.mjs http://localhost:4291
node scripts/qa-geo-import-large.mjs http://localhost:4291
node scripts/qa-navara-geo-import.mjs http://localhost:4291
Use the keyless server for every check. Photoreal-only cases remain
unverified; do not enable paid tiles to run them.
Require engine.imagery for weather and wind and load the wind flow backend
from the layer manifest. Preserve Cesium's staging, frame retention, shell
ordering, wind fade and streamlines; Navara follows the same display policy.
Remove obsolete rendering modules and their three translated status keys.
Run every weather and wind display case on both the fake engine and the
headless Cesium engine, keeping the existing behavioural assertions.
Coupling: Cesium import files fall from 27 to 25, viewer lines from 1232 to
1177 and engine-name lines from 63 to 62. The explicit Cesium wind flow
backend deliberately raises renderer lines from 330 to 344 and extension
reads from 8 to 9; every other count stays unchanged.
Browser checks to run
GOOGLE_MAPS_API_KEY= CESIUM_ION_TOKEN= npm run dev -- --port 4291
node scripts/qa-contract-suite.mjs http://localhost:4291
node scripts/qa-weather-compare.mjs shoot http://localhost:4291 --out=qa-shots/weather-after
Compare weather and wind against the previous capture on both engines.
engine.imagery gains what these rasters need, on every engine:
- geographic (EPSG:4326) tile schemes and a transform applied to each
decoded tile (the satellite infrared mask);
- staged source changes, which keep the drawn source until the new one
has loaded (the weather frame swap), and credit-only changes in place;
- raised layers that draw on a shell above terrain and 3D tiles, rising
with the camera, with a detail image inside a rectangle. On Cesium this
is the weather shell primitive, moved into the engine; on Navara the
pixel's ray meets the ellipsoid grown by the height.
Rain radar, satellite clouds, lightning, the wind field and the Bhote
Koshi event and locator each draw through one render/display.js on both
engines; their Navara renderers and Navara's weather surface pass go.
Cesium's pixels are unchanged in every compared scene. On Navara the
Bhote Koshi images are no longer upside down. Two engine-specific parts
stay behind one backend option each: the wind's streamlines and the
Bhote Koshi story entities.
The coupling report now counts defineGroundEffect calls, not its own
declaration. Coupling: Navara renderer lines fall from 2304 to 1695,
Navara ground passes from 3 to 1 (the Global Context pulses), engine
kind checks from 5 to 2. The contract suite passes on both engines
(Cesium 71/71, Navara 74/74).
Navara's ground pass cut each corridor into chunks and tested them per
screen cell, so dense corridor sets were slow (10,000 cost about 150 ms a
frame). A corridor set is now cut into pieces along its great circles,
sorted into lon/lat tiles, each with a pyramid of bins listing the
segment runs within its margin; a pixel takes its tile and the finest
bin that covers its reach and tests only those runs. At 10,000 corridors
a frame now takes 11.8 ms still (Cesium 23 ms), at 15,000 17.9 ms. A
pixel corridor's width is measured across the line, so diagonal lines no
longer draw up to 1.4 times wider.
Pixel corridors take three looks, evaluated on the GPU from a time
uniform: Cesium's PolylineGlow falloff (glow), an alpha pulse and the
annotation route's flowing dash. While a shown set pulses or flows the
engine draws continuously, as Cesium did. Traffic's jam lines take the
glow and pulse again and the Directions route its flowing dash and render
hold, so on Cesium both match the drawing before they moved to the
contract pixel for pixel. The contract suite passes on both engines
(Cesium 69/69, Navara 72/72).
src/app/layers/renderers.js now holds LAYER_MANIFEST, one entry per
layer in directory order: a display (the same render/display.js on every
engine, with the contract primitives it needs and, for CCTV and Global
Context, a Navara backend loaded by import()), a layer that draws itself
through the contract, or per-engine renderers for the layers not on a
display yet (weather, wind, Bhote Koshi, sea marks, ski pistes). A layer
is available where the engine has the primitives it needs. The Cesium
renderer table, CESIUM_BUILTIN, the registry and the Navara mode's map of
about 35 loaders go; the application loads a kind's renderers before it
builds the catalog.
The tools attach through one tree over the engine, in Cesium's order.
Each engine kind adds its own tools from one backend that reads its
extension once: the Cesium backend holds the viewer-only tools, the
Navara backend the annotation renderer, draw surface and file import
drawing.
Coupling: engine.extensions reads fall from 12 to 8, engine-name literal
lines from 73 to 66.
engine.imagery draws raster layers over the globe: Web Mercator tile
templates and single images or canvases stretched over a rectangle, with
alpha, show, a left/right split against the engine's split position and
an order. A layer's source can be replaced in place.
- Cesium puts one ImageryLayer per layer on the globe's imagery stack,
or on the shown 3D tileset's when the globe is hidden, and moves it
when the surface changes; the Recent Imagery request gate moved here.
- Navara draws them in one screen pass after tone mapping that samples up
to eight layers by geodetic position from mipmapped textures and a tile
atlas, under the other drapes and engine.ground.
- The fake engine keeps each layer's state.
The FIRMS far-zoom heat raster and Recent Imagery now draw through it, so
FIRMS' heat seam and both its backends, and Recent Imagery's Cesium and
Navara renderers and tile plan, go. Against HEAD, Cesium's pixels are
identical in all four compared scenes; Navara's orbital heat changes by a
mean of 3.8 from new mipmapping, slightly towards Cesium. The contract
suite passes on both engines (Cesium 68/68, Navara 71/71).
engine.maps.addOverlay stays a Navara-only extension for Sea Marks and
Ski Pistes until imagery has a finer tile path for oblique global views.
Navara lights the map tiles with the real sun and sky, and only the
landscape maps took the night ambient fill, so an OSM street map turned
black at local night where Cesium keeps it lit. Every base map now takes
the night fill; the landscape maps keep their orbital fill as well.
Daylight is unchanged.
This is why the strict acceptance's Navara pixel and first-frame checks
over Austin failed in evening runs: navara-hd, parked-release,
hidden-switch, context-loss, geo-import and scope saw a black frame, and
the soak and failure matrix waited for a first frame that never came.
At night with the fix all nine pass.
Earthquakes, air quality, GNSS Integrity, fire perimeters, Prohibited &
Restricted Airspace, Active Fires, S2 GhostMaps, cyclone advisories and
submarine cables each have one render/display.js on the globe contract;
their render/cesium* and render/navara* files go. Their discs, cells,
polygons and corridors are engine.ground sets, so on Navara they come from
the one ground screen pass with exact colours instead of nine hand-written
classification passes and lit SDK vector layers. Cesium's look stays the
reference:
- Earthquake and air-quality discs have no outline (Cesium drew none on
clamped ellipses); earthquake discs can now be picked on Navara too.
- Perimeters, drone zones and GhostMaps polygons outline their outer
ring only, as Cesium did.
- GNSS cells stay out of the pick pass; cyclone cones, tracks and centres
are culled by a port of Cesium's horizon occluder.
- Submarine cables are one ground corridor set, as Cesium batched them;
landing points, tips and stems are movers and lines.
- FIRMS glows are a sprite set and its cells a ground set. The far-zoom
heat raster, which no primitive draws yet, sits behind one seam,
render/heatField.js, with a Cesium and a Navara backend.
The shared Navara ground helpers that only these layers used go
(navaraGroundCells, the cell and ground geometry, the zone renderers), as
does the ground prototype script.
Coupling: layer renderer lines fall from 1636/6953 to 1011/4832
(Cesium/Navara), Navara ground passes from 7 to 5, Cesium-importing files
from 65 to 53, engine.extensions reads from 26 to 19.
engine.ground draws sets of polygons (with holes), discs, cells and
corridors draped on the surface, with fill and outline colours, order and
picks, written in bulk and committed. Every engine implements it:
- Cesium batches each set into one GroundPrimitive for fills and one
GroundPolylinePrimitive for outlines and pixel corridors, classified
against terrain and 3D tiles; sets that are not pickable stay out of the
pick pass.
- Navara draws them in one screen pass after tone mapping that finds each
pixel's ground from the scene depth and tests the items in its screen
cell; long rings are split into edge bins. Measured at Dubai against
SDK vector layers, the pass matched Cesium's frame time up to 10,000
polygons with a few megabytes instead of 70 to 146, drew exact colours
and outlines, and hid reliably across an engine switch, where vector
layers hidden with update({ show: false }) never hid. Dense corridors
remain its limit (10,000 cost 135 ms a frame).
- The fake engine keeps the same registry and CPU picks.
The contract suite checks it on both engines (Cesium 66/66, Navara 69/69).
Earthquakes and fire perimeters have unwired ground prototypes whose
drawing matches today's Cesium one (0.998 on Cesium, 0.976 on Navara).
docs/GLOBE-PRIMITIVES.md describes the primitives and when to use each.
- Radio: stations, clusters, the selection and its brackets are point
and sprite sets; clusters come from the layer's engine-neutral screen
clusterer with Cesium's EntityCluster rules, and clicks go through the
selection dispatcher. One style module holds the sizes and colours.
- Transit: vehicles are two sprite sets from an up-front atlas, rotated
with Cesium's projected-rotation maths. The selected vehicle's trail is
engine.lines in two lanes and 29 age bands, so trails are no longer
draped over terrain until the contract has ground corridors. The
Cesium contact trail renderer and its re-export go.
- CCTV: markers, wedges, the plane outline and the calibration gizmo
(rings, arrows, handles, drags through engine.input) draw on the
contract. The textured monitor plane and the viewshed volume, which no
primitive expresses yet, sit behind one seam, render/meshes.js, with a
Cesium backend and a Navara backend the Navara mode passes in.
Known gaps against Cesium: transit trails are not draped, and the
surveillance-lens click correction runs only where the engine reports
its style stage (Navara).
Coupling: layer renderer lines fall from 2638/8735 to 1636/6953
(Cesium/Navara), ScreenSpaceEventHandler files from 15 to 10, `viewer`
lines from 2014 to 1901.
Each layer now has one render/display.js on the globe contract, the same
factory on both engines; its render/cesium* and render/navara* files go.
Cesium's behaviour is the reference, and the logic that was written twice
is written once:
- AIS vessels: atlas chevrons and engine.lines trails. The display
registers the gev-trail pick claim itself and its trailing visibility
pass now also runs on Navara.
- Satellites: point banks per look, orbit rings as lines turned by their
model matrix, and selection and follow through engine.camera.follow.
The emulated _viewer is gone, and the tracked readout republishes card
text on Navara too.
- Space Missions: dots, reticle, trajectories and tactical orbits as
movers and lines. The layer keeps its own records instead of Entities
and DataSources, and camera work goes through engine.camera. Clicks go
through the selection dispatcher, and hover keeps Cesium's throttle. The
pad zone is its rim only: the contract has no surface fill yet.
- ALPR, bikeshare and OSM Places: one display and, for bikeshare, one
style module each; clicks through engine.input, no
ScreenSpaceEventHandler or EntityCluster. ALPR keeps Navara's horizon
cull, and OSM Places points sample the surface where Cesium clamped them.
Coupling: layer renderer lines fall from 4546/11106 to 2638/8735
(Cesium/Navara), `viewer` lines from 2209 to 2014, ScreenSpaceEventHandler
files from 20 to 15.
In the app the world overlay draws on a canvas of its own above the
globe, so letting every canvas take the pointer sent the suite's clicks
there. Only the engine's canvas takes it now. Without makeCanvas the
pick check's sprite atlas was a plain object no real engine draws, so its
sprites could not be picked; the page now hands the suite real 2D
canvases. --only=prefix,... runs a subset of the checks. With both, Cesium
passes 63 of 63 checks and Navara 66 of 66.
The layers that still had one Cesium and one Navara implementation, or
drew on Cesium only, now draw through engine.movers, engine.lines and
engine.camera on both engines, and application code holds the engine
instead of guessing it from a viewer.
- Aircraft family: flights, military and local ADS-B share one display
(src/layers/aircraft/render/display.js). The Cesium and Navara
renderers are gone. Where they differed, the display follows Cesium:
- attach and visibility tracking, live disableDepthTestDistance
changes, the tracked glyph's distance scale, model ids that change,
local ADS-B markers hidden until shown and its UAT ring as a point;
- the trail head's hidden alpha is 0.45, the contract's
depthFailAlpha scaled by the head's 0.9.
The tracked glyph stays over the fleet, as on Navara. The movers
contract reports readiness per model and reads model axes as the
glTF's own on every engine. Cesium's follow takes any native target
through a proxy entity in the ENU frame and mirrors its readout fields.
- Wildlife Sightings draws badges and the density glow as sprite sets
and its privacy cells as line outlines (no fill yet). It takes clicks
from engine.input and its card anchors to the engine's canvas and
camera, so the layer is in both engines' catalogs again and a switch
keeps the session's layer set.
- Cockpit: cockpitHost takes the engine only. The ridden aircraft is the
engine follow's target, hidden through its sprite; only the Cesium
Viewer's stock double-click is still routed around.
- About forty camera, navigation, share-link, HUD, voice, detection and
layer-lifecycle callers take the engine. isGlobeEngine and
engineFromViewer calls outside src/globe fall from 51 to 14.
The coupling baseline drops accordingly: layer renderer lines from
5239/12331 to 4546/11106 (Cesium/Navara), `viewer` lines from 2424 to
2209, Cesium-importing files from 69 to 66.
Layers are to draw through the globe contract on both engines, so Cesium
gets back the movers and lines removed as unused:
- engine.movers draws sprite sets as a BillboardCollection (atlas cells
cropped once per set), point sets as a PointPrimitiveCollection and
model sets as one Model per instance. depthTest, disableWithinM, order,
scaleByDistance, colorBlend, unlit and minimumPixelSize follow the
contract; a model's matrix is written in place, so instances no longer
share one scratch matrix.
- engine.lines draws each line as a polyline Primitive with width in CSS
px, geodesic arcs, dashes, the tactical and arrow materials,
depthFailAlpha and modelMatrix; a rebuild keeps its show, matrix,
colour and place in order.
- The picker returns the pickId a layer wrote last, skips sets that are
not pickable and instances behind the horizon, and falls through to
what lies under them. Surface samples can exclude mover sets again.
movers and lines move from the optional capabilities into the required
contract shape, and the contract suite always runs their checks.
scripts/report-engine-coupling.mjs counts the engine-specific code left
outside src/globe/cesium and src/globe/navara: layer renderer lines per
engine, Cesium imports, `viewer` mentions, engine-name checks, raw Navara
reads, Navara ground passes, Cesium SDK loads and ScreenSpaceEventHandler
users. engineCoupling.test.mjs fails npm test when a count grows past
scripts/engine-coupling-baseline.json, so each step towards drawing
through the globe contract can only lower them.
scripts/qa-contract-suite.mjs runs src/globe/testing/contractSuite.mjs in
headless Chrome on the Cesium and Navara of a keyless dev server, which
until now only ran on the fake engine. The page imports the suite from the
dev server, starts at a fixed view, waits for the camera to rest and lets
the pointer through the panels. Cesium passes 57 of 57 checks, Navara 64
of 67; docs/CURRENT-STATE.md names the three that fail.
Main's camera, voice, Cockpit and layer work now runs on the globe
contract where this branch draws through it:
- The voice tilt to an angle, its pivot about the place under the
crosshair and the frame limit from orbit run through the camera rig;
src/globeInView.js measures a camera pose with src/geo instead of a
Cesium camera. The free-look height limit and the globe-in-view
recovery stay Cesium-only for now.
- Cockpit takes main's own-layer entry rule. Double-clicking the
followed track goes through cockpitHost.routeDoubleClick, so it works
on both engines.
- Space Missions' failed-entry rollback and GhostMaps' age filter run
in the engine-neutral layer code. On Cesium an expired report is
dropped in place; on Navara its product is redrawn.
- Wildlife Sightings joins the catalog Cesium-only: Navara leaves it
out, and the shell builds its card only for the real layer, so a
Navara page no longer fails to start on its stand-in.
- One instruction sentence is shorter, which keeps the Realtime prompt
within its 55,500-character budget with the Sentinel-2 basemap.
Review fixes on top of #1578:
- Exiting Space Missions cancels the layer's own camera flights again (entry,
roster preview, mission focus); only a flight navigation started after
releaseCameraOwnership() runs on.
- A failed first index load says so: "Space Missions unavailable: the
mission index could not load. Try again later." on both the Context and
Data Layers routes, instead of a generic transition toast. Translated.
- Regression tests for both; docs and changelog describe the real feedback.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Review fixes on top of #1601:
- Only redirect a provider the params switch on to a keyless source, so a
filter-only setParams (360°, SINCE) no longer moves an explicitly chosen
keyless Mapillary to KartaView.
- Keyless QA gate: assert the new KartaView default and that the Mapillary
chip explains its key instead of switching (it used to expect KEY REQUIRED).
- Tests: Graph-proxy keyReady, filter-only updates; shared test helper.
- README and CURRENT-STATE describe the keyless default.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
- Keep the open card across a widened reload only when its index still
holds the same report; the server may answer a pinned version with newer
bytes.
- Narrowing to a window the loaded data already covers clears a failed
wider reload, so the row no longer stays in error.
- Label the every-age option "All" (contextual) so the six-option switch
fits the row in every locale; tooltip and info line keep "All markers".
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Review fixes on top of #1528:
- Narrowing the age window only removes markers; a product loaded with a
narrower window is reloaded when the window widens again. Fixes markers
missing after 7d -> 1d -> 7d and avoids reparsing every KMZ on narrowing.
- A wider window over the same edition keeps the open report card.
- Date-only event dates cover their whole UTC day, so 1d still shows
yesterday's reports.
- The age options are one labelled "Event age" radio switch (row
`segmented` control, as FIRMS confidence) instead of toggle chips mixed
with the product chips.
- Un-nest the per-product age test; QA compares data-source counts with the
live defaults instead of a hard-coded 2.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
- Publish classificationName next to the raw NHC code; unknown codes stay
unexpanded.
- Publish staleCacheFetchedAt only while the proxy serves its cache.
- Touch the shared store on clear only after this layer published, so a
feed failure no longer evicts another layer's dangling selection.
- Drop the unreachable no-storm branch and the unused return value.
- Tests: split the heading fixture into due north and stationary, cover
the unavailable and failure paths with the real store, and check that
clear/disable leave another layer's selection alone; fold the fake-store
test into the real-store one.
Navara now draws at CSS pixels without MSAA, like Cesium; Navara HD keeps the device pixel ratio and MSAA 4. Only one Navara variant is ever kept. A parked engine is released after three minutes and its WebGL context is lost. Three leaks that kept a released Navara alive are fixed, the canvas context drops its unused antialias buffer, cloud shadows use two 256 px cascades, and the tile cache is budgeted from the screen buffers.
From 400 km, a tilt to -5° that a zoom out x2.5 caught 70 frames in eased down from the camera's old pitch at the new range. That put the camera below the place's horizon: the first frame's crosshair hit the ground 186 km from London, and London stayed hidden for about 11 frames. The re-solve also left the pivot pitch at 0°, so a zoom in before the next frame computed an infinite clearance floor, was refused, and stayed at 1,000 km.
The re-solved pivot pitch now stops at the place's horizon limit, or where the pivot already was. A camera that the zoom leaves past that limit steps down to it with the zoom and holds it, and the zoom still reports that angle. A zoom in straight after brings the range back to 400 km.
From 400 km, a tilt to -5° that a zoom out x2.5 caught at -8.0005° reported -8°, and the next frame jumped to -9.407° and ended there. The zoom kept the camera's pitch as the goal when it was already past the new range's horizon limit, but at the same pivot pitch the longer range looks down more steeply, so the next lookAt dropped the camera 1.4° at once.
The zoom now re-solves the pivot pitch so the new range keeps the camera's pitch, and aims the tilt at the asked angle or the new limit, even when that limit is below where the camera stands: the tilt eases down to it. The zoom's reply names that end, and the camera reaches it with no frame moving more than 0.1°.
A partial failure reset the layer's cooldown, so a camera move retried at
once. Acartia's error was discarded, an absent X-Upstream-Status hid the
HTTP 503 (the proxy's daily-budget reply), and a grid schema error masked
the observation 503. Each failed source now keeps its status and
Retry-After, the HTTP status counts when no upstream status is sent, and the
layer waits for the longest 429/5xx cooldown among them. The shown error is
the one that explains the cooldown.
The held-pointer guard was one flag, so with two fingers down, lifting one cleared it and the recovery turned the view down under the other (pitch -42° to -90°). It now tracks each pressed pointer by id and defers until the last is released.
A release outside the window that the page never sees could leave the recovery deferred for good. A lost window focus, a hidden page or a lost pointer capture now releases every held pointer, and a pointer that moves with no button down is released.
A pivot range rebuilt from the camera's position came back a hair over the 1,000 km cutoff when the view sat exactly on it, so a tilt from 1,000 km ran in place and lifted the crosshair onto the sky. The cutoff now allows 1 m of slack.
A zoom during a tilt to an angle changes the range the pivot holds, and with it the place's horizon limit, but the tilt kept its old goal and its reply its old angle: from 400 km, a tilt to -5° zoomed out x2.5 reported -5° with no note and ended at -9.4°. The zoom now re-judges the goal at the new range, eases the tilt from where it is to it, and its result names the angle the tilt now ends at, with a note.
/grid/{z}/{x}/{y}.grid.json is documented in the v1 and v2 API docs as
Grid Tiles UTFGrid; only its per-cell records are unspecified, which is
what the schema guard covers. DATA_SOURCES.md now also notes that
Acartia's README asks API users to create an account and an API key,
although /sightings/current answers without one today.
An iNaturalist rejection discarded a successful Acartia reply, and the
antimeridian Promise.all lost both halves when one failed. Each box now
settles independently; the failed part is reported on
sources.inaturalist (error and failed boxes), the layer keeps that
area's last iNaturalist rows and shows DEGRADED with retry timing, and
the update fails outright only when every requested source failed.
The card's "Acartia" link was built from the contributor-supplied
photo_url, so any https site could appear labelled as Acartia. Acartia
has no documented per-sighting page, so the source link is now always
the Acartia site, on the server projection and again in the card.
The separate "Open on Acartia" fallback link is no longer needed.
A quiet or fully filtered feed raised invalid_snapshot, so the proxy
answered 502 with a 15 s cooldown and re-polled about four times a
minute. Only a non-array payload is malformed now; an empty projection
caches for the normal ten minutes and clears earlier rows.
German Khokhlov