Apple uses SVGs (Scalable Vector Graphics) for their navigation items for several reasons:
Scalability Without Quality Loss: SVGs are vector-based, meaning they can scale up or down without losing image quality. This ensures that the navigation icons look sharp and clear on a wide range of screens and resolutions, which is crucial for providing a consistent user experience across different devices, from iPhones to Macs with Retina displays.
Smaller File Size: Compared to raster images like PNGs or JPEGs, SVG files tend to be smaller in size when optimized properly, which helps in faster loading times for web pages and apps. This is particularly important for ensuring smooth and responsive navigation interfaces.
Resolution Independence: Because SVGs are not bound to a fixed resolution, they are inherently high-resolution. This makes them ideal for high-density displays, ensuring icons look perfect without the need for multiple image assets for different screen resolutions.
Styling Flexibility: SVGs can be styled and manipulated using CSS and JavaScript. This allows for impressive design possibilities, such as dynamic color changes, animations, and other interactive effects, which can enhance the look and feel of navigation items.
Accessibility and Search Engine Optimization: SVGs can contain textual information that is recognizable by search engines and screen readers, improving both accessibility for users with disabilities and the website’s SEO.
Cross-Browser Consistency: SVGs are well-supported across all modern browsers, ensuring that navigation elements will render consistently for all users, regardless of their browser choice. This helps maintain a consistent user experience, which is crucial for a brand like Apple known for its focus on design and user satisfaction.

These advantages make SVGs a suitable choice for Apple as they aim to deliver high-quality, efficient, and visually appealing interfaces.