The makers of electronic shelf labels defend their polarizing rollout by retailers like Kroger, while consumer advocates, including Sen. Elizabeth Warren, sound the alarm about how the tech will raise prices for Americans. Perusing the grocery aisle in the Westside Market on 23rd Street in Manhattan, you might not even notice the screens. They look just like paper price labels and, alongside a bar code, use a handwriting-style font we’ve come to associate with a certain merchant folksiness. They’re not particularly bright or showy. The only clues that they’re not ordinary sticky shelf labels are a barely distinguishable light bulb and, on some, a small QR code.