This Open in Browser 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 4,400 icons, all in the same style and quality.
This is a picture of a browser window. It's blank for the most part, and on top has a bar with two black circles and a rectangular bar on the right side of that. There is a large curved arrow pointing into the box, pointing upwards.