tileUrlTemplate

The file:// URL template rememberRasterDemTileSource (hillshade) can use to reach source's downloaded tiles directly, matching TerrainTileStore's own <baseDir>/<source>/<zoom>/<x>/<y>.webp layout.

baseDir is always an absolute path (see terrainStorageDirectory's platform actuals), so this yields a three-slash file:///... URL — see OfflineTerrainRepositoryTest's template test for why that is asserted explicitly rather than left to be "fixed" to four slashes later.

The directory portion is percent-encoded before interpolation — a Desktop/JVM user-data path can legitimately contain characters reserved in a URL (a space in a Windows/macOS username is the common case, #/% less so but just as real) — while the trailing {z}/{x}/{y} placeholders are appended afterwards, literally, so rememberRasterDemTileSource's own substitution still sees them unescaped.