Google Earth API/plugin has been deprecated due to browsers removing support for NPAPI plugins for security reasons.
To view KML and KMZ files in web-based applications, you can use CesiumJS, Google Maps API, or a variety of other map libraries. Cesium can be used to create 3-D globe or 2-D map-based views.
In Cesium its 1 line of code:
viewer.dataSources.add(
Cesium.KmlDataSource.load('../../SampleData/facilities.kmz')
);
You can find an online example that loads KMZ files onto a 3D globe.
Navigate to DataSource tab in the Gallery for the KML example.
Cesium has tutorials on migrating from Google Earth API to Cesium.
http://cesiumjs.org/for-google-earth-developers.html