I am not a pro but this is how understand it - Game logic is coded into script files. AND If you modify running game script file, you can change the logic it contains, for example, change of clothes when you level up - if you put command for it as false, then your deck will show clothed girl only. Do note that Modifying the script may make the game corrupt if not done correctly.
In the past, I have merged scripts for the game "The Witcher 3" while adding mods i liked and modified game script file for the game "Elder Scrolls V Skyrim". MODS may contain game script if it involves changing game mechanics. I do not know how advanced players can change game script(s) for an 'online' game like this one. The ones who have joined Discord channel can tell you more.
Banning foreign scripts should have been done way earlier to prevent cheating. Maybe the player base size was small earlier and only advanced players can inject/modify running game scripts - so it was sort of neglected.