A massive part of the CUSA00900 modding scene revolves around and save editing. Save Wizard is a commercial software ($60/year) that lets you decrypt PS4 saves to apply cheats.
(Undead Giant’s Cut Phase)
Not all with blood on their hands were monsters. There arose, gradually, a cohort of those who sought to use the old knowledge without surrendering to it. They were craftsmen who took the Choir's diagrams but applied them not to ascetic ritual but to tools that could ease suffering. Their instruments were less like relics and more like reason made physical: prosthetics that harnessed the tremor of the hand, small devices to staunch the worst of the contagion's first days. They were not saints; saints were not needed. They were pragmatic, stubborn, human. Bloodborne v1.09 -DLC Mods- -CUSA00900
Thus, when you see a mod that requires "Bloodborne v1.09 | CUSA00900," it is demanding this specific fingerprint. A massive part of the CUSA00900 modding scene
III. Of Mirrors and Mirrors Broken