...Developers can define complex collection views from items, groups, sections, and dimensional rules instead of writing extensive custom layout subclasses. The same approach can create lists, grids, mosaics, nested groups, banners, and independently scrolling sections. An interoperability file helps projects share layout code between systems using the native API and those using the backport. The library closely mirrors Apple's API so migration requires minimal conceptual changes. It was created to reduce duplicate layout code during the transition to newer UIKit versions.