Damage Indicator(Heart Particles) was added in 1.9.
This feature was not really helpful for me, because it sometimes blocks players' screen and even causes the lag.
So this mod was made for people who are like me.
What does it do?
It's very simple : it completely removes damage indicators(heart particles) through mixins.(also fixes the lag)
It blocks the heart particles from spawning, which is why it could fix the lag.