How to upload products to Facebook?

Question

Facebook

I am uploading IM products for Facebook. The documentation says the following:

<rss xmlns:g="http://base.google.com/ns/1.0" version="2.0">
<channel>
<title>Test Store</title>
<link>http://www.example.com</link>
<description>An example item from the feed</description>
<item>
<g:id>DB_1</g:id>
<g:title>Dog Bowl In Blue</g:title>
<g:description>Solid plastic Dog Bowl in marine blue color</g:description>
<g:link>http://www.example.com/bowls/db-1.html</g:link>
<g:image_link>http://images.example.com/DB_1.png</g:image_link>
<g:brand>Example</g:brand>
<g:condition>new</g:condition>
<g:availability>in stock</g:availability>
<g:price>9.99 GBP</g:price>
<g:shipping>
<g:country>UK</g:country>
<g:service>Standard</g:service>
<g:price>4.95 GBP</g:price>
</g:shipping>
<g:google_product_category>Animals > Pet Supplies</g:google_product_category>
<g:custom_label_0>Made in Waterford, IE</g:custom_label_0>
</item>
</channel>
</rss>

Explain what this line means, do you need to enter your site here?

<rss xmlns:g="http://base.google.com/ns/1.0" version="2.0">

The second point - it's not clear why in the example all the tags start with g?
https://www.facebook.com/business/help/12507438148...