Iron Golem. Why so vague on new Thorns damage

Ok So maybe I misunderstood something or there is some resource somewhere I haven’t seen.
So Thorns now does flat damage when attacked and when hit instead of a percent of damage done. Ok so…how much damage? Does this damage go up with points invested into Iron Golem? Do synergy points invested into fire golem also increase thorns damage of the iron golem? All I see is “thorns damage” in the description of the skill. It used to show a percentage of damage reflected now… nothing.
So can anyone explain this. Since Blizzard is supposedly working on spell notes being more descriptive, why did they decide to go backward on the notes for the iron golem.