Ftp and other 69,000 icons from Icons8 icon pack follow the visual guidelines of the operating systems: Windows, iOS, Android KitKat, and Material. PNG format is free up to 100x100 px. Icons are availble for download in PNG and vector (SVG, PDF, EPS, and more).
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.