You can find the .jar files for various Minecraft versions (e.g., 1.20.1, 1.21.1) on official sites like CurseForge and Modrinth .
This is a critical mod library used as a dependency for many popular mods like Atmospheric or Upgrade Aquatic .
If you are looking for the Minecraft technical library or mod:
A specific mod that allows you to map out builds before creating them using a feather, paper, and blue dye. 2. Developing a "Story Jar" Download Blueprint jar
To use it, download the appropriate version's .jar file and place it into your Minecraft %appdata%\.minecraft\mods folder.
