Most modding tutorials here begin with "rename tons of files to guess where PNGs are".
Why would you though?

The game stores its data in simple ordered gzip compressed entries.
File list is just hidden in the first entry - 0.dat.
You can extract the original directory filename using this crude tool in C# (source included).
Just a little bit more convenient.

https://drive.google.com/file/d/1KKdOhBfp-oTaEOdShbEo6a0hZAQJ_FsP/view

Usage:

• Copy fightnextract.exe to your game folder
  
• Double click the tool
  
• Check assets folder