Most perks have a perk entry that describes the effect and amount (e.g. Agile Defender: Mod Armor Rating X%). It's easy to make changes and create a custom perk. However, about 30 or so perks have no perk entry listed. So, for example, how does Intense Flames cause "targets to flee if their health is low"? Where can I see the details of that perk and make changes?