Linear region file format uses about half of the original Anvil region file without any loss of data.
Check this repository for documentation and tools.
This fork is 100% compatible with Paper, it just reads and saves region files in .linear instead of .mca.
Great for giant (TB+) worlds. Offers no advantages for tiny worlds, it's just a region file format.
./gradlew applyPatches
./gradlew createReobfPaperclipJar
Your compiled .jar will be in build/libs/.