From the ReadMe, roughly translated: Matercrack / Des-flash-Emp_dev - Unpacking and packing of dev_flash
This is a script used to unpack and pack the PUP dev_flash the team using tools fail0verflow, kakaroto and geohot, although modified a bit for better performance.
0. Put these tools in a folder called flash-Des-Emp_dev
1. You need to have unpacked the PUP
2. Extract the files in the folder update_files.tar script
3. Run the script and ready
Note: This script creates 3 folders dev_flash, dev_flash_temp dev_flash3 and the first two are simply dev_flash fully unpacked and the third is the creation of folders dev_flash .* files, this could change what you wanted (I AM NOT RESPONSIBLE FOR THIS MAY CAUSE DAMAGE TO TOOL) and modify the script to skip to step packaging.
WARNING: I AM NOT RESPONSIBLE FOR DAMAGE THAT MAY CAUSE THIS TOOL BE CAREFUL.