When exporting a map with points to kml from the Yandex Map Map Designer, the KML file contains HTTP links to icons like http://api-maps.yandex.ru/i/0.4/micro/pmbls.png When loading such KML via ymaps.geoXml. load Chrome gives the mixed content error even if you replace the links to the icons after loading:
ymaps.geoXml.load('https://****/test.kml').then(function (res) { res.search('geometry.type == "Point"').each(function (item) { item.options.set('iconImageHref', item.options.get('iconImageHref').replace(/^http:/,'https:')); }).addTo(clusterer);
})
In this case, all the icons are displayed, but for each type of icons is given for 1 warning about the mixed content.
As a workaround, you can manually convert KML, but you are interested in a complete solution.