5.17 http://schemas.microsoft.com/office/spreadsheetml/2016/revision3 Schema

 <xsd:schema targetNamespace="http://schemas.microsoft.com/office/spreadsheetml/2016/revision3" elementFormDefault="qualified" xmlns="http://schemas.microsoft.com/office/spreadsheetml/2016/revision3" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:x="http://schemas.openxmlformats.org/spreadsheetml/2006/main">
   <xsd:import namespace="http://schemas.openxmlformats.org/spreadsheetml/2006/main" schemaLocation="xlbasictypes.xsd"/>
   <xsd:attribute name="uid" type="x:ST_Guid"/>
 </xsd:schema>