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  "road_source": "OpenStreetMap (local PBF extract)",
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  "osm_snapshot": "2026-08-12T20:21:46Z",
  "elevation_provider": "Environment Agency",
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  "notes": "Coarse pass: max 19.8% over 200 m (Terrain 50), gain 55.9 m over 289 m way. EXTENDED by graph walk: +1 segment(s) at base, +4 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting."
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}