Is custom tab in word document is supported?

Question

I'm trying to add a custom tab in word document (version 16.63.1 )as below (Content of manifest file). But i do not see the new tab. Is there any mistake in this code?
<ExtensionPoint xsi:type="ContosoRibbonTab">
<CustomTab id="Contoso.TabCustom2">
<Group id="CommandsGroup">
<Label resid="CommandsGroup.Label"/>
<Icon>
<bt:Image size="16" resid="Icon.16x16"/>
<bt:Image size="32" resid="Icon.32x32"/>
<bt:Image size="80" resid="Icon.80x80"/>
</Icon>
<Control xsi:type="Button" id="TaskpaneButton">
<Label resid="TaskpaneButton.Label"/>
<Supertip>
<Title resid="TaskpaneButton.Label"/>
<Description resid="TaskpaneButton.Tooltip"/>
</Supertip>
<Icon>
<bt:Image size="16" resid="Icon.16x16"/>
<bt:Image size="32" resid="Icon.32x32"/>
<bt:Image size="80" resid="Icon.80x80"/>
</Icon>
<Action xsi:type="ShowTaskpane">
<TaskpaneId>ButtonId1</TaskpaneId>
<SourceLocation resid="Taskpane.Url"/>
</Action>
</Control>
<Control xsi:type="Button" id="Contoso.FunctionButton">
<Label resid="Contoso.FunctionButton.Label" />
<Supertip>
<Title resid="Contoso.FunctionButton.Label" />
<Description resid="Contoso.FunctionButton.Tooltip" />
</Supertip>
<Icon>
<bt:Image size="16" resid="id1"/>
<bt:Image size="32" resid="id2"/>
<bt:Image size="80" resid="id3"/>
</Icon>

              <Action xsi:type="ExecuteFunction">  
                <FunctionName>doSomethingAndShowDialog</FunctionName>  
              </Action>  
                
            </Control>  
            <OfficeControl id="Superscript" />  
            <InsertAfter>TabHome</InsertAfter>  
          </Group>  
        <Label resid="customTabLabel1" />  
      </CustomTab>  
    </ExtensionPoint>