Schottky diode polarity attiny85 dev board
As it is now, it prevents back-feeding the 5V to PC.
Whether that is the intention or not, is unknown. Most likely it is an error in the schematic as that device is supposed to be USB-powered.
That circuit also pulls the USB data line to 5V, and uses 5V MCU and zener diodes ro clamp voltages to 3.3V.
If anything in that circuit fails, it will destroy an USB port, so don't plug it into your only or most expensive PC, rather get a device with real USB interface.