Does the repo use its own safetygym files?

[Gricha1]

Hi, thanks for the big contribution in safeRL field. There was mentioned that this repo doesnt contain safety_gym repo(also readme doesnt mention anything about it). So i downloaded it manually, but i have noticed files in
https://github.com/ZikangXiong/MFNLC/tree/master/mfnlc/envs

This is a modification of files from safety_gym repo(such as engine.py). Should i use these files in SafetyGym instead original one? What type of modification was made in these files, is it related only to env render, or maybe somehow change the robot models?