It is a logo of a heat map. there is a 90 degree right angle located at the bottom left and inside the right angle are various sizes of circles. Some circles small some big. The bigger the circles are it is indicating the higher in temperature the heat is.
This is a Heat Map 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.