Unfortunately & oddly enough, that is not a feature of Airtable. The Airtable Team custom-designed that sidebar for their Universe website, but it is actually not a part of the product at all. Welcome to the wacky world of Airtable! You might want to add that as a feature request in the #show-and-tell:product-suggestions topic.
Thanks @ScottWorld for the intel and the reply. this is not a super smart move on their behalf, of course it’s a better design and we’ll all want it. gah. I upgraded just so I could figure it out. Anyway, guess I’ll add the request to the list. Thanks!