With every major version, we always see the configuration file updates. The major change I had seen was in Sitecore 7.2 to Sitecore 8.x and then in 9.x. I had expected the same in Sitecore 10 as well.
I mostly go through Sitecore.config and ConnectionStrings.config first once Sitecore Vanilla instance of latest version is installed. The connection strings config is similar to 9.x version but I saw something strange in Sitecore.config.
I saw an empty Sites node in Sitecore.config.

This made curious to find the all site nodes. And then notepad++ search feature helped me to find the config file where all these site nodes are moved. The new file where it is moved is Sitecore.Sites.config at the path – \App_Config\Sitecore\CMS.Core

I hope this will save your time of exploring such setting changes. I will update new findings in my upcoming blogs.
Thank you.. Keep Learning.. Keep Sitecoring.. 🙂