Managed to find it, it only works on Windows, it is a batch file, and it alters the ffdata_slot_1.sav (autosave slot), so read it or scan it if you're concerned.
Since it modifies the save slot itself, I would make a manual save to a different slot just so you don't lose anything.
To use it, just make sure you're not in game when you run it, either be out of the game or the main menu. After running it'll give you a prompt to walk you through the things it can do. Then just load the first slot.
Things it can do:
Change level
Unlock/Lock all powerups
Change ideals
Things it can't do:
It can't unlock achievements directly, therefore it can't unlock the gallery. Although it should make getting some achievements easier.
Give databanks (I could do this, it'd take awhile for me to get it figured out)
Give fragments (this one would be harder to do, but maybe it'd work, I really don't know)
Alter level progression (theoretically I could do this, but it'd take some time)
Alter Faye reputation (maybe I could do this, I'm really not sure due to how this value is saved)
Alter previous character choices (even if I knew how to do this, there are so many alterations and whatnot, I probably won't do it, although I could add a function to delete all choices pretty quick, I haven't seen any issues in progression doing this manually, but who knows)
Disclaimer: Since this thing doesn't change the flags and values associated with character choices, it might break some cutscenes. So maybe start a new game, save at the first pad, then use it just so if anything you'd have fewer checks in place than the game would expect.
Mega