This Zamknięty temat 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 4,300 icons, all in the same style and quality.
This icon is a circular speech bubble, with a curved point at its bottom coming from the bottom left. Inside the speech bubble is an icon of a lock, which is a small rectangle with a hole in the middle and a curved line on top.