Updating child theme after upgrade to 1.1

By Jim Gasperini
January 13, 2018, 5:31 pm EST
The "Version 1.1 Changes" page says in part: "Created a child theme. Remember that if only want to change CSS styles, there’s no need to use a child theme; just use the Add CSS option in the Customizer (if you have JetPack turned on). Use this child theme if you want to make functionality changes.
Note: Folks already using a child theme will likely need to update their enqueue functions."
Where is the newly created child theme? It did not appear in the list of themes when I upgraded to 1.1. Assuming I can find it somewhere, are there any advantage to using this new child theme? Should I start over with a new child theme? If I can still use my old child theme, I will need to figure out how to update its "enqueue functions." Any pointers would be appreciated.