Yarn is a set of open, unencumbered Minecraft mappings, free for everyone to use under the Creative Commons Zero license. The intention is to let everyone mod Minecraft freely and openly, while also being able to innovate and process the mappings as they see fit.

To see the current version being targeted, check the branch name!

To use yarn-deobfuscated Minecraft for Minecraft modding or as a dependency in a Java project, you can use loom Gradle plugin. See fabric wiki tutorial for more information.

To obtain a deobfuscated Minecraft jar, ./gradlew mapNamedJar will generate a jar named like <minecraft version>-named.jar, which can be sent to a decompiler for deobfuscated code.

Please note to run the yarn build script Java 17 or higher is required!

Please remember that copying and pasting mappings from alternate projects under more restrictive licenses (such as MCP, Spigot's or Mojang's obfuscation maps) is completely forbidden without explicit permission from the owners of said mappings to distribute the names under the CC0 license. This includes using the names from those mappings for inspiration. Discussing the naming approaches used in said projects is also not welcome - you have been warned. However, it is a good idea to consult name changes with other people - use pull requests or our community spaces to ask questions!

Please have a look at the naming conventions before submitting mappings.

1. Fork and clone the repo
2. Run ./gradlew yarn (Linux, macOS) or gradlew yarn (Windows) to open Enigma, a user interface to easily edit the mappings
3. Commit and push your work to your fork
4. Open a pull request with your changes

Yarn uses Gradle to provide a number of utility tasks for working with the mappings.

Setup and download and launch the latest version of Enigma automatically configured to use the merged jar and the mappings.

Compared to launching Enigma externally, the gradle task adds a name guesser plugin that automatically maps enums and a few constant field names.

Same as above, but unpicks the constants and launches Enigma with them. Can be a little bit slower to get going.

Same as yarn, but will only show common classes.

Build a GZip'd archive containing a tiny mapping between official (obfuscated), intermediary, and yarn names ("named") and packages enigma mappings into a zip archive..

Builds a deobfuscated jar with yarn mappings and automapped fields (enums, etc.). Unmapped names will be filled with intermediary names.

Decompile the mapped source code. Note: This is not designed to be recompiled.

Downloads the client and server Minecraft jars for the current Minecraft version to .gradle/minecraft

Merges the client and server jars into one merged jar, located at VERSION-merged.jar in the mappings directory where VERSION is the current Minecraft version.

Formats and sorts the mappings, ensuring that they are in a consistent order.