Add a color relief layer

Replicates the MapLibre example Add a color relief layer: the Innsbruck Alps colored by elevation, from deep blue at 400 m to red at 3,500 m.

The complete document

# yaml-language-server: $schema=https://docs.maplibre-yaml.org/schema/latest/map.schema.json
# Gallery twin of https://maplibre.org/maplibre-gl-js/docs/examples/add-a-color-relief-layer/
# A color-relief layer (maplibre-gl >= 5.6) tints a raster-dem source by
# elevation: color-relief-color is a ramp over ["elevation"].
type: map
id: add-a-color-relief-layer
config:
  center: [11.45, 47.2]
  zoom: 10
  maxZoom: 18
  renderWorldCopies: false
  mapStyle:
    version: 8
    sources: {}
    layers: []
layers:
  - id: color-relief
    type: color-relief
    source:
      type: raster-dem
      url: "https://demotiles.maplibre.org/terrain-tiles/tiles.json"
      tileSize: 256
    paint:
      color-relief-color:
        - interpolate
        - ["linear"]
        - ["elevation"]
        - 400
        - "rgb(4, 0, 108)"
        - 582.35
        - "rgb(5, 1, 154)"
        - 764.71
        - "rgb(10, 21, 189)"
        - 947.06
        - "rgb(16, 44, 218)"
        - 1129.41
        - "rgb(24, 69, 240)"
        - 1311.76
        - "rgb(20, 112, 193)"
        - 1494.12
        - "rgb(39, 144, 116)"
        - 1676.47
        - "rgb(57, 169, 29)"
        - 1858.82
        - "rgb(111, 186, 5)"
        - 2041.18
        - "rgb(160, 201, 4)"
        - 2223.53
        - "rgb(205, 216, 2)"
        - 2405.88
        - "rgb(244, 221, 4)"
        - 2588.24
        - "rgb(251, 194, 14)"
        - 2770.59
        - "rgb(252, 163, 21)"
        - 2952.94
        - "rgb(253, 128, 20)"
        - 3135.29
        - "rgb(254, 85, 14)"
        - 3317.65
        - "rgb(243, 36, 13)"
        - 3500
        - "rgb(215, 5, 13)"

What to notice

color-relief is a layer type like hillshade. It draws from a raster-dem source, and its color-relief-color is a ramp over the ["elevation"] expression, the way heatmap-color ramps over ["heatmap-density"].
The basemap is an inline empty style, exactly as upstream, so the relief is the whole map.
Needs maplibre-gl 5.6 or later. On an older runtime the renderer skips the layer with one console warning (a declared absence) and the rest of the document renders. It does not let MapLibre reject the style.
Export class: exports. The layer compiles through to style.json verbatim. mlym emit --target below 5.6 reports it as lossy, because that runtime cannot draw it.