KML format is subtype of application/xml with a "kml" root node and (an optional?) "http://www.opengis.net/kml/2.2" namespace.
<root-XML namespaceURI="http://www.opengis.net/kml/2.2" localName="kml"/>
<_comment>Keyhole Markup Language</_comment>
KMZ files (https://developers.google.com/kml/documentation/kmzarchives) are zip archives with a KML file inside (the file should be called doc.kml) and one or more folder. A naive approach consists in adding a further check in ZipContainerDetector (find attached).