HMCL (Hello Minecraft! Launcher) is a cross-platform Minecraft launcher written in Java using JavaFX. It manages game instances (install, update, launch), downloads game files and mod loaders (Forge, Fabric, NeoForge, Quilt, LiteLoader, etc.), supports multiple authentication methods (offline, Microsoft, Yggdrasil, authlib-injector), and handles modpacks (CurseForge, Modrinth, MultiMC, etc.). The architecture is a monolith with three modules: HMCL (UI), HMCLCore (core logic), and HMCLBoot (bootstrap). It features a custom task framework for async operations, an event bus, a wizard system for multi-step dialogs, and extensive hardware detection (CPU, GPU, memory) across Windows, macOS, and Linux. The codebase is well-structured but contains copied external libraries (JFoenix skins, APNG reader) and some tight coupling between UI and core modules.