The legality depends entirely on the source.
Once you have the mei fifi zip file top, follow these steps to avoid errors: mei fifi zip file top
.mtl file (material file) points to ./textures/ and not C:/Users/Admin/Desktop/.After extraction:
ls -la
cat flag.txt # or cat readme.md
The flag might be inside:
CTFmei_fifi_top_unlocked
(or whatever the actual string is.)