librarianlib-1.12.2-4.4.jar is a release file of the Minecraft data pack [IR] Polish Railway Infrastructure, made for Minecraft 1.12.2. It was published on January 13, 2018 and is 2.3 MB in size. For the full description, screenshots and every other version, visit the [IR] Polish Railway Infrastructure data pack page.
How to install: Put the .zip into the datapacks folder of your world (.minecraft/saves/<world>/datapacks) and run /reload. No mods needed.
