ChestShop is a mature Bukkit/Spigot/Paper plugin that enables players to create and operate shops using chests and signs. It provides a full economy-driven trading system: players place a sign on a chest to define a shop, set prices, and buy/sell items. The plugin handles shop creation, transaction validation, inventory management, and economic transfers, with extensive integration hooks for popular protection and economy plugins (Vault, Reserve, WorldGuard, GriefPrevention, PlotSquared, Lockette, etc.). The architecture is event-driven and modular, with a core plugin module and version-specific adapter modules to support Minecraft versions from 1.13 to 1.20.5. It uses a custom configuration system with annotations, a lightweight database layer (SQLite via ORMLite), and a comprehensive localization system supporting 40+ languages. The codebase is well-structured with clear separation of concerns, but carries technical debt from deprecated Bukkit APIs, manual database migrations, and tight coupling to many external plugin APIs.