Polar ( hollow-cube/polar )
A world format for Minestom designed for simpler and smaller handling of small worlds, particularly for user generated content where size matters.
Minestom ( Minestom )
Minestom is an open-source library that enables developers to create their own Minecraft server software, without any code from Mojang.
Quick facts
- Edition: Minecraft Java
- File type: .jar
- Minecraft version listed: 1.21.9
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on Modrinth — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — see the MC Java Mods guides for the full walkthrough.
Verified by MCModsHub
- Ships as polarconverter-2025.10.13-m-1.21.9-p-1.15.0.jar — drop this file into the mods folder
- Download size: 34.8 MB
- Download link checked 31 Aug 2026 — working
These come from our own check of the pack file, not from the source page.