This is the First Negative Rebuttal, or 1NR. Coming right after the 2NC, the Negative has another 5 minutes in high school (6 in college) to dump offense against the Aff.
The 1NR has a surprising advantage – prep time. The 1N had the entire 2NC to prep their speech, so it should be very strong. To take advantage of this, Neg teams will often put the most important position in the 1NR, giving the 1N an entire speech to just dump arguments on the most important source of Neg offense.