Unpack YU-RIS engine package file (?), which is used by NEKO-NIN exHeart, with Kaitai Struct.
Filename size "magic value" based on pyge extract script <https://github.com/shish/pyge/blob/master/archive/YPF.py> by @shish, with further addition and modification. If I ever figure out the analytic solution to the filename size, I will rip out the switch-case hack. But for now, that will have to do.