5.5 http://schemas.microsoft.com/office/word/2018/wordml Schema

 <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:w12="http://schemas.openxmlformats.org/wordprocessingml/2006/main" elementFormDefault="qualified" attributeFormDefault="qualified" blockDefault="#all" xmlns="http://schemas.microsoft.com/office/word/2018/wordml" targetNamespace="http://schemas.microsoft.com/office/word/2018/wordml">
   <xsd:import id="w12" namespace="http://schemas.openxmlformats.org/wordprocessingml/2006/main" schemaLocation="word12.xsd"/>
   <xsd:complexType name="CT_Extension">
     <xsd:sequence>
       <xsd:any processContents="lax"/>
     </xsd:sequence>
     <xsd:attribute name="uri" type="xsd:token"/>
   </xsd:complexType>
   <xsd:complexType name="CT_ExtensionList">
     <xsd:sequence>
       <xsd:element name="ext" type="CT_Extension" minOccurs="0" maxOccurs="unbounded"/>
     </xsd:sequence>
   </xsd:complexType>
 </xsd:schema>