It's a logo of GG reduced to two capital letter G's. The two letters are enclosed in a circle and are interconnected with one another.
This GG icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 5,700 icons, all in the same style and quality.