what are small codechanges that have a big impact with the new ui and apis

At WWDC 2025, Apple introduced several small code changes that can have a significant impact on app design and functionality. Here are some highlights:

1. Liquid Glass Effects: The new design system introduces Liquid Glass, which enhances the appearance of UI elements like tab bars and sidebars. This effect is automatically applied to many existing views when you recompile your app with the new SDKs, providing a fresh look without requiring code changes. For more details, you can check the session Build a SwiftUI app with the new design.

2. Toolbar Enhancements: New APIs allow for more customization of toolbars, including the ability to section and style items. The Toolbar Spacer API helps create additional groupings, which can improve the organization and usability of your app's interface. This is discussed in the Platforms State of the Union.

3. Search and Navigation Updates: The search experience has been updated for consistency and ease of use across platforms. For example, the search tab in tab-based apps now morphs into the search field, providing a more intuitive user experience. This is covered in the session What’s new in SwiftUI.

4. Performance Improvements: Incremental changes like inserting new items in lists are significantly faster, with some operations being up to 16 times faster. This can greatly enhance the performance of apps with large data sets. More details can be found in the Platforms State of the Union.

These updates demonstrate how small code changes can lead to substantial improvements in app design and performance, making it easier for developers to create more engaging and efficient applications.