This is a Timezone UTC 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 12,900 icons, all in the same style and quality.
It is an icon for timezone UTC. There is an outline of a folded map that is opened up. The map has nothing but dots inside of it. In the bottom right of the icon, there is the number 0 that covers about a quarter of the map.