Spoke protector is another name. And those tabs do break off fairly frequently. Then the things slop around when the wheel spins and make lots of noise. At the shop, we replace them when they are broken and generally recommend them on low to mid level bikes. Sometimes I get a wheel without one in which the chain has been shifted into the spokes. Many to all of the in-facing spokes on the cassette side will be gouged and need to be replaced.