A university student mirrored a Claude Code source snapshot that became publicly accessible on March 31, 2026, due to a source map (.map file) exposure in the npm package distribution. The exposed TypeScript sources were hosted in Anthropic's R2 storage bucket and included ~1,900 files and 512,000+ lines of code. The repository provides an architectural breakdown of Claude Code's internals, covering its tool system (BashTool, FileReadTool, AgentTool, MCPTool, etc.), command system, service layer, bridge system for IDE integration, permission model, and feature flag system. The tech stack includes Bun, TypeScript, React+Ink for terminal UI, Zod, MCP SDK, and OpenTelemetry. The repo is framed as a defensive security research and supply-chain analysis archive.