The icon is shaped like the letter U but it is not fully completed. The bottom left part of the icon sticks out a bit and forms a tear like shape that looks like it is dripping downwards.
This is a Mu 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 13,700 icons, all in the same style and quality.