Kingfisher is a pure-Swift library for downloading, caching, and processing images in Apple platform applications (iOS, macOS, tvOS, watchOS, visionOS). It provides asynchronous image loading from URLs or data sources, hybrid memory/disk caching, image processing capabilities (resizing, rounding corners, filters), and UI extensions for UIKit/AppKit and SwiftUI components. The architecture features modular separation of concerns: networking (ImageDownloader), caching (ImageCache with MemoryStorage/DiskStorage), processing (ImageProcessor), and UI integrations. Key entry points include UIImageView.kf extensions, KFImage SwiftUI view, and KingfisherManager.shared for programmatic control. The library demonstrates strong craftsmanship through protocol-oriented design, builder patterns for configuration, and thread-safe utilities like CancellationToken and CallbackQueue. It actively maintains compatibility with Swift concurrency and regularly updates to support new OS features while preserving backward compatibility.

Rainbow is a zero-runtime-dependency Swift library that applies ANSI escape sequences to strings for colored terminal output. It supports the named 16-color palette plus light variants, 8-bit 256-color mode (38;5;N), 24-bit true color (38;2;R;G;B), hex colors approximated to the nearest 256-color cube, HSL colors converted to RGB, and styles (bold, dim, italic, underline, blink, swap, strikethrough). Output is gated by OutputTarget detection that checks isatty() on POSIX/Windows plus NO_COLOR/FORCE_COLOR environment variables, so redirected output degrades to plain text automatically.