Real build failure once the tmp-filename fix got past the format- detection error: "data/sources/lake_centerline.shp.zip does not exist. Run with --download to fetch it". The OpenMapTiles profile needs a few small non-OSM sources (water polygons, Natural Earth, lake centerlines) alongside the .osm.pbf itself, and Planetiler only fetches them when told to. They land under its own default data/sources/, gitignored alongside the rest of data/ — fetched once, reused by every later build.