Not a MBTiles file format.

[felagund]

I am not sure I am following the docs well enough (they are not that clear) but I downloaded a map from here:
https://download.geofabrik.de/south-america/chile.html

and then I ran:

java -Xmx6G -jar mapsplit-all-0.4.0.jar -tvMm -i chile-latest.osm.pbf -f 2000 -o chile1.msf -z 15 -O 2000 -s 200000000,20000000,2000000 -p chile.poly

But when I try to load the resulting file in Vespucci, I get an error "Not a MBTiles file format". Is there further modification needed to this command? What am I doing wrong?