There is a rectangle with the top right hand corner folded over towards the center. In the center of the rectangle is a capital letter "R" and a capital letter "A" and another capital letter "R".
This is a RAR 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 13,100 icons, all in the same style and quality.