5.31 http://schemas.microsoft.com/office/drawing/2017/03/chart Schema

 <xsd:schema targetNamespace="http://schemas.microsoft.com/office/drawing/2017/03/chart" elementFormDefault="qualified" attributeFormDefault="qualified" xmlns="http://schemas.microsoft.com/office/drawing/2017/03/chart" xmlns:c="http://schemas.openxmlformats.org/drawingml/2006/chart" xmlns:xsd="http://www.w3.org/2001/XMLSchema" blockDefault="#all">
   <xsd:import namespace="http://schemas.openxmlformats.org/drawingml/2006/chart" schemaLocation="chart.xsd"/>
   <xsd:complexType name="CT_BooleanFalse">
     <xsd:attribute name="val" type="xsd:boolean" use="optional" default="false"/>
   </xsd:complexType>
   <xsd:complexType name="CT_DataDisplayOptions16">
     <xsd:sequence>
       <xsd:element name="dispNaAsBlank" type="CT_BooleanFalse" minOccurs="0" maxOccurs="1"/>
     </xsd:sequence>
   </xsd:complexType>
   <xsd:element name="dataDisplayOptions16" type="CT_DataDisplayOptions16"/>
 </xsd:schema>