The defaults remains the same: Bay area at zoom 15.
The key, if not supplied, is taken from the environment.
```
Allowed options:
-s [ --style ] URL Map stylesheet
--north degrees (=37.200000000000003) North latitude
--west degrees (=-122.8) West longitude
--south degrees (=38.100000000000001) South latitude
--east degrees (=-121.7) East longitude
--minZoom number (=0) Min zoom level
--maxZoom number (=15) Max zoom level
--pixelRatio number (=1) Pixel ratio
-t [ --token ] key Mapbox access token
-o [ --output ] file (=offline.db) Output database file name
```
2b0749e3c6