It's a square with a QR code in the bottom right corner. There's a little oval at the top. The square is behind a rectangle, which is over the bottom half of the square.
This is a Scan Stock 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 13,300 icons, all in the same style and quality.