Google Shopping feed

<?xml version="1.0"?>
<rss xmlns:g="http://base.google.com/ns/1.0" version="2.0">
  <channel>
    <title>Example - Google Store</title>
    <link>https://store.google.com</link>
    <description>This is an example of a basic RSS 2.0 document containing a single item</description>
    <item>
      <g:id>TV_123456</g:id>
      <g:title>Google Chromecast with Google TV</g:title>
      <g:description>Chromecast with Google TV brings you the entertainment you love, in up to 4K HDR</g:description>
      <g:link>https://store.google.com/product/chromecast_google_tv</g:link>
      <g:image_link>https://images.example.com/TV_123456.png</g:image_link>
      <g:condition>new</g:condition>
      <g:availability>in stock</g:availability>
      <g:price>49.99 USD</g:price>
      <g:shipping>
        <g:country>US</g:country>
        <g:service>Standard</g:service>
        <g:price>7.99 USD</g:price>
      </g:shipping>
      <g:gtin>123456789123</g:gtin>
      <g:brand>Google</g:brand>
      <g:product_detail>
        <g:attribute_name>Material</g:attribute_name>
        <g:attribute_value>Cotton</g:attribute_value>
      </g:product_detail>
    </item>
  </channel>
</rss>

<item>
  <!-- ... other fields ... -->
  <g:product_detail>
    <g:attribute_name>Material</g:attribute_name>
    <g:attribute_value>Cotton</g:attribute_value>
  </g:product_detail>
  <g:product_detail>
    <g:attribute_name>Care Instructions</g:attribute_name>
    <g:attribute_value>Machine washable</g:attribute_value>
  </g:product_detail>
</item>