Hi Alexander,
Kmz ->Topojson
Results does not see in QGIS, conversion succeeded.
Link to screencast:
https://app.screencast.com/etcR3d4wLzH7k
Attached samples: input/output/QGIS.
Bug 4571 KMZ to TopoJson -results d…... Your source KMZ contains MultiPolygonZ...src = Drivers.Kmz.Open(@"C:\Data\input.kmz")) { // Prepare conversion...