The .pofo file format was presumably created by Tekken57 for his X-Packer tool. It contains the section from memory/saves where the moveset of a wrestler is stored. It was adopted by Caveman's Data Editor followed by TheVisitorX ' Custom Character Tools and Pozzum's WWE2k17+ which all support this format.
This file type is different for various games. This section breaks down this file type per game.
A Breakdown of this File Type in WWE 2K17.
A Breakdown of this File Type in WWE 2K16.