This Ftp 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 file folder symbol with the wi-fi network symbol in the upper right corner. The wi-fi symbol has been transposed to fit within the corner and it is shown upside down with the smallest dot at the top rather than the bottom. The wi-fi symbol is also at a 45 degree angle rather than straight up and down which is how the icon is normally visualized.