The icon is shaped like a horizontal rectangle. In the very center of it is a question mark punctuation. Under the rectangle you can slightly see another one underneath it sticking out.
This is a Questions 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 13,900 icons, all in the same style and quality.