You have 2 options:
For the code part of it, you can look at DNSpy (link in one of my previous comments, but you can find it easily). With it, you can decompile the Assembly-CSharp.dll. From then, reading the code is pretty straightforward, even if there is a lot of it.
In order to inspect ingame values, you can use UnityExplorer (Included with the mod). You can make the interface visible with F7, the class that contains most of the data is called StaticDataManager.
If you just want to make a copy of an existing card, you can directly copy it from there. You don't have to do it manually, you can just do something like
C:
StaticDataManager sdm = SimpleSingleton<StaticDataManager>.Instance;
SkillEntity sk = (SkillEntity)sdm.skillMap["SC001_01"].MemberwiseClone();
sk.id = card_id + "_01"; //Repeat for every skill
MoreCardsManager.RegisterSkill(card_id + "_01", sk, new SC001_01());
CardEntity cd = (CardEntity)sdm.cardMap["SC001"].MemberwiseClone();
Code:
public class SC555_01 : SC001_01
{
}This should be everything you need. The only caveat is that some effects are tied to the specific IDs of the Squeezers, meaning they cannot be copied as-is. These are Bunnygirl's coop effect, Schoolgirl's 2, and Iron's ability to not die when killed.
