5.21 http://schemas.microsoft.com/office/spreadsheetml/2017/richdata Schema

 <xsd:schema targetNamespace="http://schemas.microsoft.com/office/spreadsheetml/2017/richdata" elementFormDefault="qualified" xmlns:x="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns="http://schemas.microsoft.com/office/spreadsheetml/2017/richdata" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
   <xsd:import namespace="http://schemas.openxmlformats.org/spreadsheetml/2006/main" schemaLocation="xlbasictypes.xsd"/>
   <xsd:element name="rvData" type="CT_RichValueData"/>
   <xsd:complexType name="CT_RichValueData">
     <xsd:sequence>
       <xsd:element name="rv" minOccurs="0" maxOccurs="unbounded" type="CT_RichValue"/>
       <xsd:element name="extLst" type="x:CT_ExtensionList" minOccurs="0" maxOccurs="1"/>
     </xsd:sequence>
     <xsd:attribute name="count" type="xsd:unsignedInt" use="required"/>
   </xsd:complexType>
   <xsd:complexType name="CT_RichValue">
     <xsd:sequence>
       <xsd:element name="fb" minOccurs="0" maxOccurs="1" type="CT_RichValueFallback"/>
       <xsd:element name="v" minOccurs="1" maxOccurs="unbounded" type="CT_Value"/>
     </xsd:sequence>
     <xsd:attribute name="s" type="xsd:unsignedInt" use="required"/>
   </xsd:complexType>
   <xsd:complexType name="CT_Value">
     <xsd:simpleContent>
       <xsd:extension base="x:ST_Xstring"/>
     </xsd:simpleContent>
   </xsd:complexType>
   <xsd:element name="rvStructures" type="CT_RichValueStructures"/>
   <xsd:complexType name="CT_RichValueFallback">
     <xsd:simpleContent>
       <xsd:extension base="xsd:string">
         <xsd:attribute name="t" type="ST_RichValueFallbackType" use="optional" default="n"/>
       </xsd:extension>
     </xsd:simpleContent>
   </xsd:complexType>
   <xsd:simpleType name="ST_RichValueFallbackType">
     <xsd:restriction base="x:ST_Xstring">
       <xsd:enumeration value="b"/>
       <xsd:enumeration value="n"/>
       <xsd:enumeration value="e"/>
       <xsd:enumeration value="s"/>
     </xsd:restriction>
   </xsd:simpleType>
   <xsd:complexType name="CT_RichValueStructures">
     <xsd:sequence>
       <xsd:element name="s" minOccurs="0" maxOccurs="unbounded" type="CT_RichValueStructure"/>
       <xsd:element name="extLst" type="x:CT_ExtensionList" minOccurs="0" maxOccurs="1"/>
     </xsd:sequence>
     <xsd:attribute name="count" type="xsd:unsignedInt" use="required"/>
   </xsd:complexType>
   <xsd:complexType name="CT_RichValueStructure">
     <xsd:sequence>
       <xsd:element name="k" minOccurs="1" maxOccurs="unbounded" type="CT_Key"/>
     </xsd:sequence>
     <xsd:attribute name="t" type="xsd:string" use="required"/>
   </xsd:complexType>
   <xsd:complexType name="CT_Key">
     <xsd:attribute name="n" type="x:ST_Xstring" use="required"/>
     <xsd:attribute name="t" type="ST_RichValueValueType" use="optional" default="d"/>
   </xsd:complexType>
   <xsd:simpleType name="ST_RichValueValueType">
     <xsd:restriction base="x:ST_Xstring">
       <xsd:enumeration value="d"/>
       <xsd:enumeration value="i"/>
       <xsd:enumeration value="b"/>
       <xsd:enumeration value="e"/>
       <xsd:enumeration value="s"/>
       <xsd:enumeration value="r"/>
       <xsd:enumeration value="a"/>
       <xsd:enumeration value="spb"/>
     </xsd:restriction>
   </xsd:simpleType>
   <xsd:element name="rvb" type="CT_RichValueBlock"/>
   <xsd:complexType name="CT_RichValueBlock">
     <xsd:attribute name="i" type="xsd:unsignedInt" use="required"/>
   </xsd:complexType>
 </xsd:schema>