eacc860b_rver_7_0_0_beta1_documentation__MapServer_equivalence_Notes
[Document element] StyleSelector [Supported] Yes [MapServer equivalence/Notes] 
Style element will be supported. All different styles from the layers will be stored here and referenced from the folders using a styleUrl.In addition to the Styles related to features, there is a ListStyle element added at the document level. This allows to control the way folders are presented.See Layers section (styleUrl) setting for more details.
MS RFC 58: Kml Output — MapServer 7.0.0-beta1 documentation