Ok, it seems like a lot of people here think dark matter is a “thing” but it’s not. Dark matter is simply unaccounted for mass in the universe. When we discover mass that we didn’t know about before, the amount of “dark” matter decreases. The word “dark” here merely means “known unknown” because we observe the effect but not the cause. This discovery has unveiled some of the dark matter as baryon particles in a plasma. So some of that dark matter is now known.