Rounds are a new type of ammunition introduced in the 2023 remaster of Quake II. They are used as ammunition for the Disruptor. The Disruptor was a piece of unused content that was designed for Ground Zero, but was cut from the game before its original release. The 2023 Remaster officially adds the Disruptor into the game, as well an ammo pickup for it; the Rounds.
Each pickup of Rounds confers 3 shots. They are fairly uncommon; they (and the Disruptor itself) only appear in the Ground Zero campaign and in one unit of Call of the Machine. However, the 2023 remaster also includes three Rounds in the Ammo Pack.