This icon is a part of a collection of Ustąp pierwszeńśtwa flat icons produced by Icons8. Icons follow the guidelines of iOS, Windows, and Android and are designed by a single designer, guaranteeing the consistent quality. Both PNG and vector are available.
The icon is an upside down equilateral triangle. By "upside down" is meant that, instead of resting on one of its sides, it is standing on one of its points. It looks like a letter "V" with the top closed.