manifest-localhost.xml

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<OfficeApp xmlns="http://schemas.microsoft.com/office/appforoffice/1.1"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:bt="http://schemas.microsoft.com/office/officeappbasictypes/1.0"
  xmlns:mailappor="http://schemas.microsoft.com/office/mailappversionoverrides/1.0" xsi:type="MailApp">
  <Id>1e7e38da-7ad6-429a-9c6f-81aa1b9c9344</Id>
  <Version>1.0.0.0</Version>
  <ProviderName>Contoso</ProviderName>
  <DefaultLocale>en-US</DefaultLocale>
  <DisplayName DefaultValue="Hello world"/>
  <Description DefaultValue="A simple hello world Office Add-in."/>
  <IconUrl DefaultValue="https://localhost:3000/assets/icon-32.png"/>
  <HighResolutionIconUrl DefaultValue="https://localhost:3000/assets/icon-64.png"/>
  <SupportUrl DefaultValue="https://learn.microsoft.com/office/dev/add-ins/overview/office-add-in-code-samples"/>
  <AppDomains>
    <AppDomain>https://www.contoso.com</AppDomain>
  </AppDomains>
  <Hosts>
    <Host Name="Mailbox"/>
  </Hosts>
  <Requirements>
    <Sets>
      <Set Name="Mailbox" MinVersion="1.1"/>
    </Sets>
  </Requirements>
  <FormSettings>
    <Form xsi:type="ItemRead">
      <DesktopSettings>
        <SourceLocation DefaultValue="https://localhost:3000/taskpane.html"/>
        <RequestedHeight>250</RequestedHeight>
      </DesktopSettings>
    </Form>
  </FormSettings>
  <Permissions>ReadWriteItem</Permissions>
  <Rule xsi:type="RuleCollection" Mode="Or">
    <Rule xsi:type="ItemIs" ItemType="Appointment" FormType="Edit"/>
    <Rule xsi:type="ItemIs" ItemType="Message" FormType="Edit"/>
  </Rule>
  <DisableEntityHighlighting>false</DisableEntityHighlighting>
  <VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
    <Requirements>
      <bt:Sets DefaultMinVersion="1.3">
        <bt:Set Name="Mailbox"/>
      </bt:Sets>
    </Requirements>
    <Hosts>
      <Host xsi:type="MailHost">
        <DesktopFormFactor>

          <!-- Message Compose -->
          <ExtensionPoint xsi:type="MessageComposeCommandSurface">
            <OfficeTab id="TabDefault">
              <Group id="msgComposeCmdGroup">
                <Label resid="CommandsGroup.Label"/>
                <Control xsi:type="Button" id="msgComposeInsertGist">
                  <Label resid="TaskpaneButton.Label"/>
                  <Supertip>
                    <Title resid="TaskpaneButton.SupertipTitle"/>
                    <Description resid="TaskpaneButton.SupertipText"/>
                  </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">
                    <SourceLocation resid="Taskpane.Url"/>
                  </Action>
                </Control>
              </Group>
            </OfficeTab>
          </ExtensionPoint>
        </DesktopFormFactor>
      </Host>
    </Hosts>
    <Resources>
      <bt:Images>
        <bt:Image id="Icon.16x16" DefaultValue="https://localhost:3000/assets/icon-16.png"/>
        <bt:Image id="Icon.32x32" DefaultValue="https://localhost:3000/assets/icon-32.png"/>
        <bt:Image id="Icon.80x80" DefaultValue="https://localhost:3000/assets/icon-80.png"/>
      </bt:Images>
      <bt:Urls>
        <bt:Url id="Taskpane.Url" DefaultValue="https://localhost:3000/taskpane.html"/>
      </bt:Urls>
      <bt:ShortStrings>
        <bt:String id="CommandsGroup.Label" DefaultValue="Contoso Add-in"/>
        <bt:String id="TaskpaneButton.Label" DefaultValue="Hello world"/>
        <bt:String id="TaskpaneButton.SupertipTitle" DefaultValue="Hello world"/>
      </bt:ShortStrings>
      <bt:LongStrings>
        <bt:String id="TaskpaneButton.SupertipText" DefaultValue="Open the Hello world add-in"/>
      </bt:LongStrings>
    </Resources>
  </VersionOverrides>
</OfficeApp>