It is possible to show maps made with https://www.google.com/mymaps.

After opening a map in mapsengine, you will see the id of the map in the url:

https://www.google.com/maps/d/edit?mid=zr-BpZ_NDJSc.kXDFcQ8e62kA

Rename the edit to kml in the url, so:

https://www.google.com/maps/d/kml?mid=zr-BpZ_NDJSc.kXDFcQ8e62kA

{mosmap kml='https://www.google.com/maps/d/kml?mid=zr-BpZ_NDJSc.kXDFcQ8e62kA'}

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Also working with KML renderer GeoXML. You need to add behind the url &forcekml=1, see:

{mosmap kml='https://www.google.com/maps/d/kml?mid=zr-BpZ_NDJSc.kXDFcQ8e62kA&forcekml=1'| kmlrenderer='geoxml'}

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