The logo for 0 percents is simplistic in design and is only a circle. The dark border outlines the circle and there is nothing in the center of the circle nor outside of it.
This 0 Percent 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 6,000 icons, all in the same style and quality.