Ok, here's the whole description.
"Activated when the Buccaneer Skin is applied. After triggering "Cerebral Fire", all allied heroes including Dr. Zeno will get a boost to their Physical and Magic Attack (3 times the normal amount provided to Dr. Zeno by "Cerebral Fire"). Allied female heroes will also get a 10% boost to their attack speed.
After Dr. Zeno activates his ult, the bonus magic and physical attack that ALL heroes get = "3 times the normal amount provided to Dr. Zeno by "Cerebral Fire"
They all get the same amount and the brackets specify exactly how much that will be which is based off of the value of "Cerebral Fire" X 3, very similar to Ling's ult.