Pmtiles are the vector counterpart to Cloud Optimized GEOTIFF (COG), allowing for efficient usage of mapping info from clients when the server supports a http range request.

Previous iterations of this on the vector side have either been a ton of small files(pbf) or a large file that needed a front end to serve the individual tiles (mbtiles).

At this point, you can take an OSM dump and convert it to a country level basemap in minutes on a stout machine, or hours for a continent, which you can then self host on a plain old web server with a custom style sheet.