Thank you very much of raising this up. The existing version of *.mbtiles doesn’t follow the specification of vector tile defined at https://github.com/mapbox/mbtiles-spec/blob/master/1.3/spec.md, but generated with the “Docker” from “OpenMapTiles” after some changes. That’s the reason why it gives some problems to you. Here below are the comments of the questions:
#1. The View “Tiles” is created with tables “images” and “map”, the index is created on these 2 tables to speed up the performance. In that case, we don’t need to create index for view, so not a huge problem, don’t worry about it.
#2. It’s proved to be a bug in the utility “MBTilesExtractor for .net core”, it’s has been fixed in the latest push, please pull the update to take a try. Sorry for the problem.
Besides, I was excited to let you know a complete new version of “World Streets MbTiles” will be available pretty soon (maybe one week after), following the specification 1.3. Besides “OpenStreetMap”, “Natural Earth”, more data from ThinkGeo and “OpenAddresses are integrated”, it’s well organized and has an eye-catching style. If you are interested in, please contact firstname.lastname@example.org or we will update it here when it’s available.