Strefa czasowa +12 and other 86,400 icons from Icons8 icon pack follow the visual guidelines of the operating systems: Windows, iOS, Android KitKat, and Material. PNG format is free up to 100x100 px. Icons are availble for download in PNG and vector (SVG, PDF, EPS, and more).
The icon is describing the users time zone. It is in the shape of a wavy paper thin wall with polka dots, and has a circle with the number +12 inside of it, located on the lower right section of the wavy paper thin wall.