InjectionIII is a macOS menu bar application that enables hot-reloading of Swift, Objective-C, and C++ code changes into running iOS simulators or devices without restarting the application. It works by watching for source file modifications, recompiling the changed files using Xcode's build logs, and dynamically injecting the new code into the target process using techniques like dynamic linker interposing, vtable patching, and Objective-C swizzling. The system consists of a daemon app with a file watcher and a socket server, and a client bundle loaded into the target app that performs the actual injection. It also includes additional features like method tracing (SwiftTrace), runtime code evaluation (SwiftEval), object inspection (Xprobe), and remote control. The codebase is a mix of Swift, Objective-C, C, and assembly, demonstrating deep knowledge of macOS internals, the Mach dynamic linker, and Xcode build system.