Generally (country) there is not laws against extract content from game (if you known a law in any country just show a link), that mean its legal. There are a law for distrubute in nearly all countrys. that mean illegal.
Reverse engineear i think its legal in all europan countrys at least. I don’t known in nort america.
If i remember right in nort america you can patent coding, that mean you perhaps are doing something illegal just only for write coding.
In Europe no.
Laws are diffent between continents and countrys remember.