This is a Replace icon. We've made it in iOS style, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 12,600 icons, all in the same style and quality.
It's a logo of two circular arrows which close back in on each other to make a circular design. The arrows are pointing counterclockwise with one head on the upper right and the other on the lower left. In front of each head are two dots before the other arrow starts.