Currently fragment developers can make the fragments customizable through editable elements and configuration. This story takes the customization capabilities to the next level by defining an area where page authors can add any fragment (component) they want.
The goal of defining this text area is to empower fragment developers to create fragments such as carousels, tabbed interfaces ([example|https://www.liferay.com/services/success/journey/dxp-cloud], accordions (example), ... where page authors have the freedom to choose which fragments to add in each section.
1) The current "Layouts" that are part of Section Builder are a current example of what a Fragment Container is. The fact that it supports columns is also desirable. Considering this, one way to implement this would be by adding support to "invoke" the Layout from a fragment's HTML code.
2) An example of how this would look like is: