The new section is added to the UI with Plugins features. There you can define sets of plugins, and update and delete them.
Soon you'll be able to upload your plugins and add them to the sets.
sets
By default every plugin from the set will be activated.
Use cases
Very often I use same plugins on almost every WP site I install. In majority of cases I use:
  • Yoast
  • Wordfence
  • Elementor
  • Facebook
  • Wembaster tools
Using Plugin sets I can define this in advance and use same set for every new site.