MCLegacyCross — Classic 2013–2016 Minecraft Launcher (Windows, Linux & macOS)

A pixel-accurate 1:1 recreation of the classic 2013–2016 Minecraft Launcher (1.6.89 / OLauncher style) built with Electron, React, and TypeScript for Windows, Linux, and macOS.

Features

• 1:1 Original Visuals:
  • Classic #E6E6E6 Swing UI, crisp 1px borders, classic top tabs (Update Notes, Launcher Log, Profile Editor), tiled dark bedrock news background, etched TitledBorder group boxes, and exact 190px bottom-left column alignment (Profile: dropdown + New Profile / Edit Profile buttons).
• Cross-Platform Game Engine (Windows, Linux, macOS):
  • OS-specific .minecraft and MCLegacy directories (%APPDATA%\.minecraft on Windows, ~/.minecraft on Linux, ~/Library/Application Support/minecraft on macOS).
  • Pure Node.js ZIP/JAR native library unpacker (.dll on Windows, .so on Linux, .dylib / .jnilib on macOS).
  • Platform-accurate JVM arguments (; vs : classpath separator, LWJGL 2 vs LWJGL 3 macOS -XstartOnFirstThread & -Xdock:name=Minecraft handling, Windows Intel heap dump flag).
• Built-in Isolated Java Runtime Manager:
  • Automatically downloads and manages isolated OpenJDK 8, OpenJDK 17, and OpenJDK 21 runtimes via the Eclipse Adoptium API for Windows (.zip), Linux (.tar.gz), and macOS (.tar.gz).
• Full Version & Mod Loader Support:
  • Official Mojang version_manifest_v2.json (Releases, Snapshots, Old Beta, Old Alpha).
  • Mod loader switcher per profile: Vanilla, Fabric, Forge, NeoForge, and Quilt (including full inheritsFrom parent JAR and library merging).
• Authentication:
  • Official Microsoft OAuth 2.0 Device Code flow -> Xbox Live -> XSTS -> Minecraft Services, plus Offline Profile creation.

Development & Building

# Run unit & cross-platform integration tests
npm test

# Start in development mode
npm run dev

# Build TypeScript & Vite bundles
npm run build

# Package distributables for Windows, Linux, or macOS
npm run package:win
npm run package:linux
npm run package:mac