I hadn’t been planning on watching masked dance sophisticate SBTRKT, who was playing the neighboring tent at the same time as Drive Like Jehu’s set. But I left Jehu early because it’s hard to get excited in a huge empty tent, and I walked past SBTRKT’s stage just as Vampire Weekend frontman Ezra Koenig was taking the stage to sing his part from SBTRKT’s 2014 single “New Dorp. New York.” Koenig is fun to watch in any circumstance, and he’s especially fun in this one, doing what amounts to guest-rapper duty. He’s got a confidence and swagger that can only come with leading a successful band for years, and he brought the sort of performative panache that not many of the weekend’s dance sets could claim.