Tile
One tile of raw bytes plus optional HTTP revalidation headers. The byte payload is what the server returned: PNG/JPEG/WebP for image layers, GeoTIFF/Int16/Float32 for elevation, Mapbox Vector Tile protobuf for MVT. The cache stores blobs as-is — decoding happens in the layer that consumes the source. etag / lastModified ride alongside so a subsequent network fetch can issue a conditional GET.
Constructors
Properties
Epoch-millis the cached tile was written, for a stale-while-revalidate read. Set by a cache store when freshness tracking is enabled (finite eviction staleAfter); null on network responses and on cache reads where freshness isn't tracked. CachedTileSource uses it to decide whether to kick a background refresh after serving the cached blob.
MIME-type the server reported for bytes (e.g. application/bil16, image/png, application/vnd.ogc.se_xml). Set when the bytes came from a fresh HTTP response; null for cache-only reads (cache stores typically don't persist the header).