If you are using a (recommended for beginners):
If you’re looking to learn about (textures, database edits, stadiums) for PES 2017 within legal bounds , here’s what I can offer instead: Pes 2017 Cri Packed File Maker
If your goal is learning file format internals for purposes, study the CPK specification from CRIWARE’s public docs, not cracked game tools. If you are using a (recommended for beginners):