LED Control with current sinking
Assuming you are correct and the LED is 2V, nominally that resistor will set the LED current at close to 4mA, which is enough to make it light up dimly without wasting too much power or straining the IO pin.

I can not of course speak for the original designer, but it seems a reasonable compromise. But then again, the original designer may just have thrown in a typical value, found it lit up well enough, and kept it as is.