BLU files are a type of file that is very easy to decode, and is used to store Block Craft 3d buildings. But it is would also be useful for storage of information for any other block game. The current blu is the information for the Tholos. If you are wondering where to find the BLUs, simply download the APK for Block Craft 3d, change it to .zip, extract it, then repeat this process for the other APK labled "com.fungames.blockcraft" inside the extracted folder, then go to assets/blu.
