Understanding PMTiles archives
Portable maps and tiled data
PMTiles stores a tiled map pyramid in one archive that a browser can read with range requests or directly from a local file. Vector archives can contain several named source layers.
The source-layer name identifies data inside the archive; it is different from the visual layer name used by a map style.
How to verify the export
If nothing appears, verify the archive type, source-layer name, geographic bounds and available zoom levels. A remote archive must also permit browser requests.
Opening a local archive keeps it in the browser, while entering a remote URL requests data from that remote host.