pocketmine\level\format\generic\BaseLevelProvider::saveLevelData PHP Метод

    public function saveLevelData()
    {
        $nbt = new NBT(NBT::BIG_ENDIAN);
        $nbt->setData(new CompoundTag("", ["Data" => $this->levelData]));
        $buffer = $nbt->writeCompressed();
        file_put_contents($this->getPath() . "level.dat", $buffer);
    }